10NL: villain's reasoning

[Mazzinger]

At these low limit games people seldom fold top pair. The board has to be pretty obvious (one to the flush, straight, etc.) for somebody to fold. Your check, check and over the top bet looks weak.

[FireStorm]

Keyser hit it right on the head, classic trying to outplay someone in a spot that's actually very bad. You are basically never folding out JJ here no matter what your line. In this spot it's silly to expect him to fold, and the river blank after he calls a C/R certainly doesn't help.