[Absolution]

This could definitely be your problem.

Going from .05/.1 to .25/.50 and the levels in between I haven't notice any difference. You still have huge multiway pots every hand and nobody using any semblance of post flop (or pre flop for that matter) strategy. Usually the pots are so huge that everybody goes to show down every hand. You just play good starting hands, see a higher percentage of flops with connectors and small pp, and bet for value every time you have something. If someone wakes up they hit their draw. It's simple and easy to win (too bad a good night = maybe $20).

After that you move into small stakes territory and I think you make a big jump in difficulty every level you jump up from there (depending on where you play I suppose). I was watching some of the 1/2 and 2/4 games and it was educational. Sometimes nobody even sees the flop (not happening at my levels) and when they do it's usually short handed. A lot of mistakes at the level seem to be post flop and that's more difficult to get good at (any monkey can remember starting hands and even preflop theory). Instead of getting mostly loose passives, you get mostly tight passives (although you have to be on the lookout for those loose passive tables and jump in!). They can still be exploited, but not for as much and it takes a different set of skills entirely.

Anyway, the point is that your probably right, you've got to accustomed to winning primarily by just having a better understanding of preflop strategy and some basic odds/equity math. I could be wrong, but I'd start rereading books/posts on post flop play, start using table selection techniques and concentrate more on your reads. You can no longer play ABC monkey poker and expect to win. Go down to one table and really work at it. You have to start thinking out every decision.