How much is too much?

I was up $50 and then got hit by two str8 flushes and several sets vs my big pairs. I ended up losing about $200.
So, how much is too much to lose in one four hour session before you say enough is enough and try again later?

[Forbillz]

IMO, It's not about how much you're up or down, it's about how good/bad the game is, and your position at the table.

If the game's good, I stay.

[SNOWBALL138]

Annie Duke says never lose more than 30bb in a game, but then again, she doesn't wash her feet...

[belloc]

Also, if your psyche is so fragile after taking such a big hit that you can't play good poker even against a good table, then you might need to take a break to cool off.