You were drawing to a gut shot straight on the first hand which gave u a 5.1:1 odds against success or 16.5%. If the pot odds are greater than that, say theres a $120 in the pot and you only need 20 to call, in the long run it will be a profitable bet. The pot odds are 6:1.

I usually will call but if I dont hit it on the turn and there is betting and/or rasing in front of me I'd fold the hand. If you di hit the straight though, it is going to be very profitable due to people calling with top pair or 2 pair.