here a few thoughts on the topic of the karaoke...
I. pitch matters.
enthusiasm doesn't compensate for lack of pitch. drinking more doesn't either. neither does having a lot of friends screaming with you. unless it's a very forgiving crowd, pitch matters...
II. know your limits.
even if you sing well, not all songs are for you.
III. know your role.
not everyone should be on stage. some people were meant to be in the audience having a good time.

last but not least ... throw in the towel, and have a great time!