Because seriously, I can't find one. Either I can't connect, or my latency is too low and things become unplayable. This happens with both the matchmaking and the server browser. This only happens with left4dead as well. GRAGH. Where are all the good servers?
Use the server browser, it allows you to join games and view stuff like how many players / latency / map for the server. Open console, type "openserverbrowser"
I already said it happens there as well, even if I pick a supposed low-ping server. Not that it matters since the server browser fails to find any servers half the time. >.<
Oh whoops, didn't read closely enough. Have you tried hosting a local server? That works well for me but primarily because I'm on fast Uni internet. Other than that I'm not sure what you can do. Hopefully Valve will improve the matchmaking system because frankly it blows.
Yeah, the browser fails pretty hard. Luckily a friend of mine is hosting a server on his dedi box, so we usually just go on there.
That's pretty useful advice, maybe all the thousands of Left4dead players should all get their own servers...
Sounds like you're just joining a server with a good connection but it's buckling under the stress because it's probably overloaded running ten gaming servers on one physical server. GSPs seem to be underestimating the load and replacing one 12 man TF2 server with 3 L4D servers and not bothering to check the load when they're all full and in the middle of a panic mode :|