Do I really have to be nice all the time? I'm getting tired of it.
What part of being nice are you tired of?
I'm tired of controlling my tone when speaking to people.
I'm sorry your kindness was taken advantage of, and you don't deserve the stress for wanting to be good. You shouldn't expend it to everyone then, only to the people you think are worth it. Only they deserve your kindness, not strangers.
I know a lot of people would think that I need to maintain the kindness. But to just get so tiring.
While it's always good to be kind to others, there are situations where it is not warranted. If people are taking advantage of your kindness then you do not need that kind towards them.