Earlier quoted context omitted.
Counterpoint: when people do this to me, I instinctively assume that the true reason is laziness. On top of that, I feel alienated – what, you think you're so important that you can brush me off just like that, and I'm not even worthy being given a reason? Be careful with this one. It's very much possible to state a reason and still express that you won't change your mind on the matter. Although it is more effort, yo…
I don't like giving reasons anymore because they're usually a lie. I don't write up a list of pros and cons and find there's only one con and that's the one true reason for not wanting to do it. Reasons are complicated and hard to know yourself. By saying it, the other person can find a way to show it's not true, or get another reason out of you which shows your first reason wasn't complete. People have sometimes use…
edit: I have found this especially true in family/personal matters