What happens if I am afflicted with a condition that worsens on a failed save and choose not to try to save? Do I:
This came up in a game earlier this afternoon when we decided to just stop saving against the effect that was causing us to fall unconscious.
There is no option to skip saving throws at the end of your turn.
From the Rules Compendium pg 228
If a creature is subject to an effect that a save can end, the creature makes a saving throw against that effect at the end of each of its turns.
DDI words it thusly
End of Turn: At the end of your turn, you make a saving throw against each effect on you that a save can end.
I don't see any room for a player to argue that Saving Throws are optional in any way. Do remember that only end of turn saving throws can trigger effects that worsen on a failed save. If your character can get extra saving throws in some way, then those throws will not penalize you if failed.
While it might not be RAW to forgo a save, it makes a lot of sense to me that you could choose to automatically fail a save and suffer it's effects. A good example of this is the save that you get when falling off a cliff; if you want to not fall, you get a save, but if you do want to fall for whatever reason, it makes little sense that you have to save yourself. While it might not be totally realistic that you can willingly take the negative effects of things like poison or mental debilitation, I feel like it can make some narrative sense for the heroes to fall victim so some effect, if they needed to.
A note, though: If you (or your GM) wants to stick to pure RAW, then Pat's answer is spot on.
