Left 4 Dead is my No1 so far this Generation

[Slimebeast]

2 questions:

1. If you don't no anyone IRL to play together with, is L4D still fun to play with unknowns from Xbox Live?

2. Are there problems with persons qutting during the game - and ruining it? - in random match-ups?

3. Is communication via the head-set necessary or very important?