Here are a few mistakes you'll hopefully only make once (if at all)

1. Not checking each food tray thoroughly for dentures, hearing aids, or jewelry before removing from patient's room and disposing of it. Digging through old food trays and whatever is in the trash can trying to find a tiny (expensive) artifact is no way to spend a few hours of your shift.
2. Mistaking your female patient for a male because... well, it's just hard to tell with some people. Don't try to explain your mistake by telling the patient "You know, sometimes, it's hard to tell when you're in the hospital in those gowns..." Blush, apologize, walk out.
3. Not thoroughly reading your new patient's information and, when he asks to use the restroom, instruct him that the bathroom is just right over here and you'll help him up... when he's a double amputee.
4. Assuming that just because your patient is 21 and the man with her is probably 50, he's her father or uncle. Sometimes, he's the boyfriend or husband.
5. Assuming that night shift is calm because "everyone will be asleep." Oh, no, no, no. Night shift may be staffed for sleeping patients, but I promise you, you will have Sundowner's patients who stay up screaming, hitting, cursing, trying to break out of the bed, and call the police on you. (Occasionally, the do actually call the police. Such fun.) You will have patients on detox screaming for pain meds and for someone to please get the rats out of the room. Many older people have difficulty falling asleep in a strange place and ask for sleep aids-sometimes, the sleep aids cause paranoia, hallucinations, and fear. You will spend a great deal of time trying to save patients from injuring themselves because they will all suddenly abhor the bed. One or two will sneak out to smoke and their absence will cause great panic. And half of the patients would be happy to sleep if the others weren't screaming, cussing, beating on walls, etc.
6. Neglecting to do your own full assessment on arrival, every shift, or when the patient changes floors because you "trust" the other nurse. There are times where we as nurses may not do as good a job assessing as we no doubt should. While nothing excuses doing a job halfway, things come up. A nurse might have to stop an assessment for a code, or leave to help a patient to the bathroom with the intent to come back and that patient falls. Sometimes, we as nurses just assume that since the same patient has been with us for three weeks, nothing has changed and we could save time by doing a "glance over" assessment. Some nurses, I hate to say, just don't care enough to do their job as they should. Always do a full assessment, and on admission, don't forget to look at the butt!
7. Forget to act like a professional with coworkers or patients. You and a patient may realize that you're like twins separated at birth, and with this kind of friendship a nurse might lose professional objectivity. You'll post pictures of the two of you at the hospital on Facebook, flashing peace signs. You might be more inclined to support your friend even if he's making bad decisions and you know it. You might lie for him and endanger his life. As for coworkers, if you are dating someone you work with, don't post pictures of you two making kissy faces at work. Don't always help your significant other while ignoring others who need help.
8. Assume that posting work-related pictures on social media is OK. Different places have different rules, but it's safest the never take pictures inside your workplace with the intent to display them anywhere. Some facilities will penalize you for taking a picture of you and a work partner in a blank room just wearing company uniforms. And don't post opinions about your job, your employer, that hot tech in X-ray, the patient who pooped for two hours straight, or anything that might offend, irritate, incriminate, or indicate so-and-so was there. Unless you're very sure of the policies at your facility, not saying anything is best.
9. Never neglect your common sense or judgment. If an order sounds iffy, double-check with someone. The doctor is not immune to mistakes either. He may holler and fuss, but that's better than seriously injuring your patient.
10. Finally, mistreating your coworkers is a terrible idea on many levels. Sometimes, nurses can be terrible to their assistants just like doctors can be terrible to nurses. Insulting a coworker does not improve anyone's perception of you. If someone asks a question you feel that person should know, teach them. Ranting about how stupid they are makes you look very unprofessional, arrogant, and unkind. Bad foot to get off on.

Okay on your item "4) Assuming that just because your patient is 21 and the man with her is probably 50, he's her father or uncle. Sometimes, he's the boyfriend or husband. needs to include the other way around. My husband is 14 years my junior and when I was in the hospital in January, at least 6 different persons on staff made the mistake of asking me if that was my son. Technically he could be my son; however, he is NOT and it is annoying when professionals make silly mistakes.

Never Assume!

A lot of people think I'm my sisters mother. When I went with her for her US they asked if I was "grandma". I about died. I'm 11 years older than her and only 33.....

I've done it, many times. Now I just ask, because It's impossible to tell over a certain age. A 70 year old son and 90 year old father could be brothers for all I know.

My husband is 12 years old than I am and looks older than he really is (he gets the senior discount without being asked, and without asking, despite being in his mid-40's). I look like I'm in my late 20's. When we were first dating I had a picture of us on my work area and everyone that saw the picture asked if that was my dad. Now that we have a toddler together people ask if he's granddad!

About the assuming one is a daughter or son or mother, etc. I just did it for the first time in a long time a few weeks ago. The girl was clearly a lot younger and I assumed it was the patient's daughter. Nope. Insert foot in mouth. He was good about it though....not insulted entirely, and he liked me enough to forgive because I always did my job well for him.

Always fun when a patient calls the police. Have had that happen several times at work since every patient has a landline phone in their room. Usually happens in the evening when they are sundowning.

As for the age difference definitely never assume. My boyfriend is 17 years older than me and looks older than he is. I get mistaken for looking much younger than I actually am, sometimes by more than 10 years. I always laugh when someone asks me if I am done with high school. I let them know I finished that a long time ago and than usually ask them to guess my age. Most people have a hard time believing that I am 35, was lucky to get "young genes".

Of all the great points made in this post, that age thing really hit home with you guys huh haha

Drawing electrolytes from the same am that a potassium with normal saline IV is being run. I was shocked after running the labs that the potassium had gone from being low to being high. I was able to redraw the labs from the other arm and the results were more aligned with the pt condition. But the potassium didn't just affect my lytes. The creatinine was off, as well as the CBC. I won't be making this mistake again.

Okay on your item "4) Assuming that just because your patient is 21 and the man with her is probably 50, he's her father or uncle. Sometimes, he's the boyfriend or husband. needs to include the other way around. My husband is 14 years my junior and when I was in the hospital in January, at least 6 different persons on staff made the mistake of asking me if that was my son. Technically he could be my son; however, he is NOT and it is annoying when professionals make silly mistakes.

Never Assume!

Or assuming a person's father is their SO.

Or assuming a person's father is their SO.

This is why my usual question on introducing myself is "How is everyone here related to the patient?"

Of course then there was the really creepy one in labor whose SO was her former stepfather! Things I'd really rather not know!

This is why my usual question on introducing myself is "How is everyone here related to the patient?"

My clinical instructor in OB asked that in a post-partum room where there were two school-aged kids and two adult males in addition to baby/mom.

"Sibling, sibling, husband, baby's father."

Couple had separated, mom dated and unknowingly got knocked up, couple reconciled, then mom discovered she was pregnant.

Awkward!

I may have posted this elsewhere a while ago...but a colleague once wondered what the "smelling salts" actually smelled like. Note to self...don't try this at home, kids.

Two personal rules from an ER nurse:

1) Always make sure to SEE the ride. You will only be fooled once by someone you give narcotics to who tells you their ride "is out in the lobby." You can't take back the IV narcs you just gave and now you get to keep that patient for a while unless they can come up with another ride.

2) Check everyone you discharge for an IV. You will only discharge someone once with the IV still in their arm. You will get lucky if you remember quickly and can run after them. If not, you get to call the police or local rescue squad to go to the patient's house or call them and kindly ask them to return.