Wasn't sure whether to put in under this topic

Anyway

I've been trying to find somewhere to go out tonight and I've been complaining how boring my night will be if I don't do something, to someone. Now that person has asked me to go out to some really bad thing and I don't want to go. So how do I say no without making it obvious that I'm saying no?

you stand up for your values and say NO, and you learn not to say things you don't really mean and put yourself into these things.

Honesty

You say NO. That is all. Don't make up an excuse. You should stand up for yourself and not let it bother you if that person knows you are saying no. If you truly find it wrong, then there should not be a problem.