Sometimes, there ain't no strike zone!

It's hard for me to leave fish when I can plainly see them. It's like I feel challenged to "make" them bite, and waste time fooling around with many bait/color/size changes, when I should just move on and find some active fish. I'm getting better at it, though. Now I give them 5 minutes, 10 minutes tops, then I move on to another spot.