[pokernicus]

I think correctness should be defined by whether a play has positive expecation. If your hand is a %50.0001 favorite to win, and you're facing an all-in bet, then it's correct to call in a cash game. If your opponent sucks-out and beats you, then you can simply re-buy.

This isn't so much a matter of wanting to build your bankroll slowly. If you make negative expecation plays like folding when you're a favorite, your bankroll will decrease rather than increase.

There's also a meta-game question. If people see you fold, you may get bluffed more often, which could cost you more (this is less of a concern in online low-stakes games because opponents might be multi-tabling so may not pay attention to your big laydowns).

There's a lot of variance in these games, and that's something you have to stomach at NLHE. The way to handle this is, in part, to have an adequate size bankroll. There are lots of threads that discuss this issue, but a good rule of thumb is to have about 20 buyins.