I'm starting to realise that this is a bit of a problem for me. Often, in the spirit of trying to be confident about things and rise above issues I'll often instinctively say "it's okay" or "that's fine" when actually it isn't okay. How do I let someone know this without ruining the mood or getting a reputation of being a moody arse? And is it a bad idea to think "I'll go along with it for now but let them know later that they pissed me off", because in my experience that just leads to "well now I feel bad". Is it okay for them to feel bad and for me not to care that they do?

A common example is planning to meet someone then they get caught up with something. The girl I'm seeing at the moment, once in a while she gets a bit drink and then ends up jerking me around with when to meet her. Do I need to figure out when to bail on things in these cases?