...Later, I think about things I could've said :P

Sometimes it's hard to decide whether to shut up or say it, suppress or show it, forget or avenge it. Because we're almost, always confused whether to do all of the former or the latter, we almost always end up not saying, showing or avenging and hence later we think about things we could've said, shown or avenged :P 

Yes, it's sad when people disappoint by doing things you did not expect them to do, but still worse is when people disappoint by not doing things that you, at the very least, expected them to do. What should you do? Impulse would tell you to settle scores right away. Rationale would tell you that it's probably not worth it. Although rationale, at first thought, might appear to be self-sacrificing it actually isn't. Wouldn't you rather exalt your conscience and gratify your self esteem than sound petty or unreasonable to someone who couldn't (and more importantly, didn't) stop twice to think about it. Wouldn't you rather let your ego take the back seat when being calm can be so much better; if nothing else it might just shame one into realization, if not then you know where you stand. So, what should you do? Do what makes you happy but more importantly do what relieves you of "later thinking about things that you could've said" :)