tips of advice from personal experience:
1- Choose a profil name and stick with it, dont change your name if you want people to remember you and recognize you.
2- Never make eye-contact while eating a banana.
3- avoid holding in a fart when there's a chance you might sneeze.

little bits about myself and thoughts:
i find it interesting how most of the people i meet on l4d2 have plenty of friends in common with me, l4d2 gamers are truly a community. its like a small town where everybody knows everybody, even if you dont know someone, if you talk to them you ll find out you have many friends in common.