Be yourself and be your best self. No matter how you change, someone will find fault.
When I was a teen-ager, I worked as a checker in a grocery store. The first few weeks when I was new and nervous, this same man would get in my line every week. Each week, I did some small thing wrong - count back his change wrong, not give him his receipt quickly - and he always cussed at me. Finally, with a little experience, I checked him out PERFECTLY. He stood there a minute, turned to go, turned back around...and cussed me out anyway. Those people account for a certain percentage of the population you're going to have to always deal with. You go, Miss Perky! I'd love to be perky, but teenagers killed my perky gene.