what affects roi the most?

[fnord_too]

Oh, and since there is no real answer (it depends, yada yada yada), I voted for what I thought was closest: calls. The biggest mistakes are made in calling IMO, but also to be successful one has to make good calls. Pushing, unless you are dealing with (or are) an utter moron, will usually not be too big a mistake ever. (Things that get one into the moron category are making really huge overbet bluffs or bets that will only be called by a better hand while not folding any worse ones, bluffing when someone is obviously pot committed and certain to have you beat, etc. When you have FE, and you are not massively overbetting the pot, pushing may be a mistake, but rarely will it be a big one.)