It's not that nursing has a higher incidence of awful people - I honestly don't think that. All professions have their challenges, bad people, unhappy people, etc. The corporate sector, for example, can have a very bad workplace culture in that people can be quite intolerant towards anybody who might be perceived as 'different' (in Australia anyway, the corporate sector isn't a particularly diverse field, unlike nursing which has all different cultures, walks of life and this makes nursing a good field to work in). The corporate sector can also be very snobby, and the right clothing, makeup, shoes and outward appearance is considered important, whereas nurses are more tolerant towards people's appearance (given the nature of the job!). Not to bag the corporate sector (I work in this field now) but it is a good example of a workplace that nurses often wish they'd ended up in when they have a bad day and trust me, it aint all it's cracked up to be
I think the reason nurses might come across badly sometimes is that they are more honest than people working in offices (some of these folks can be very passive aggressive in their approach). Nurses tend to 'tell it how it is' whether you like it or not! It is a very different job to an office job, in that you see things which are traumatic, and you see people at their very lowest and worst point.
As others have said, do your research! Ask your tutors and fellow students which hospitals have a good reputation for workers, do volunteer work to get a feel for the working environment and use your clinical tutes to do the same thing. When you attend interviews, ask about the workplace culture, ask how new nurses are treated and whether there is a good team approach. Be part of the solution - treat your fellow nurses with respect.
If I listened to everyone who said to me when I started nursing (can't imagine you being a nurse, nursing is horrible, you'll just empty bed pans all day, etc) I would never have done it. Despite all the difficulties, the dodgy people you meet sometimes, nursing has given me an insight into human beings I would never have had, and I feel also that nurses are good people, for the most part, and are perceived that way by the community and I feel good for being a part of a profession which is beneficial to people. I also feel proud of my nursing skills - I did things that most people I know would never have been able to do! Nurses are brave IMO.
Be positive! Don't let people who are venting, unhappy or a regretful of their choice of profession get you down - this is something you will need to get used to as it happens from time to time. Trust your own instincts and do your research and also, when people outside of health make ignorant comments, educate them! Make them see what nurses do and how great the occupation is.