Even When You’re Sure

Don’t muck your cards until you’re sure your beat. I made this mistake and it cost me $6.  Here’s the situation.

I’m in the BB with 53o with 1 limper and the small blind. It’s checked around to the river. 

Board:

K 4 7 10 J

The SB checks, thinking there is no way I can win, I muck my cards and the limper checks. Both show 23s. My 5 would have played. I still kick myself for that.