river call too light?

On the turn, I called a smallish bet with middle pair and a weak kicker, figuring the price was too good to fold given the stack sizes. River came a blank, he bet half pot, and for some reason I convinced myself his range was mostly missed draws, so I called again. Lost to top pair with a better kicker - nothing dramatic, just felt gross.

I keep running into spots like this where I'm not sure if I'm just leveling myself into thin calls. I get the math on pot odds, but when villain's population tendencies lean more towards value betting than bluffing in these spots, am I just leaking? When do you guys decide enough is enough and throw away the bluff-catching urge?