I've gotten so used to it now - that I often will wait until a series has two or three seasons under its belt to watch. Netflix is notorious for cancelling series without warning, often after renewing them.

Painful cancellations?

* Now and Again (after 1 season)
* American Gothic (1 season)
* Angel the Series (S5 was the last season and it had just gotten good)
* Firefly (oh so painful)
* BattleStar Galatica v.1 (2 seasons, maybe three?)
* Farscape (I wisely waited to watch this until after it got it's four hour movie wrap-up - that happened due to a fan campaign.)