Meeting people can be exciting; however this really only applies to people you already know. Meeting someone or a group of people you've never hung out with before can be scary. The moment before meeting these new possible friends is what I like to call "pre-tense".
There are two forms of pre-tense: being overly confident and goofy, and being uptight and no-mistakes serious. Either way it's the feeling you get when you don't know what the outcome of a new social situation will be. I, myself, lean towards the confident and goofy route because being serious and trying to impress someone new is way too difficult. I also feel being goofy is a good way to filter out those who are focused too much on self image.
My conclusion is that if you are meeting friends in your circle, you become confident and goofy. If you are meeting friends outside of your circle (friends of your spouse, family, etc) - you become serious and try to make no mistakes. Remember, this only happens before you get into the new situation.
Once you are there...
Party on! Almost every time I've encountered a new situation, I've learned something new and have had a great time. Very rarely did I come out of a situation and didn't end up enjoying it. So why is there a pre-tense? Why is that we know deep down inside something is going to be so much fun but yet we feel discouraged? I'd say the old saying of "all work and no play makes for a dull boy" comes into play.
So what have we learned? Try and have more fun and lighten up. Everyone has their moments of working hard and trying to do the right thing, but if you don't live a little you won't see what the world truly has to offer.
Pre-tense. Post-celebration.