First off: I don't know if anything of this is really true. I just don't know people exactly and this is my perception and ONLY a perception.
I don't know. Usually, when someone says they quit being nice I find it hard to believe that they were accommodating. Maybe I am wrong, but everyone I ever knew calling themselves nice actually wasn't, but rather the opposite.
Yeah, I am not a nice person. I never was and I will never be. Yeah, a lot of people call me nice, helpful and whatever, but come on that's what everyone gets to hear all day long.
Yeah, I spend working a lot and I spend my money for others and I have all my stuff second-hand because of that. I spend all night being awake, because there are people who rely on being. Yeah, on my way home I will bring your book to the library, so you won't be stuck in the traffic. Yeah, I feel better buying fair-trade goods - no actually, stuff that pays higher than fair trade stuff. But don't we all have something like that? I work more than 50 hours a week, spend most of my free time helping others and write here only because there really isn't anything else I can do right now - well besides thinking about what I could do better or sleeping (unlikely), when they need help (and someone always does), just to not feel like a bad person.
But come on, everyone else does so too and most people on this planet do way, way more or else things wouldn't run as day do. And if everyone else is like that how does it make sense to call you nice?
Okay, there are exceptions for all of this of course, but just because someone isn't a lazy asshole it doesn't make them nice or extremely accommodating, does it? And if someone has time to write a long article on how they are so accommodating are they really?
P.S.: I slept about 3-4 hours per night last year, because there always was stuff to do and I (really) worked until I fell asleep. I guess it affected me mentally, but people rely on me.