"If they still seem a little reluctent, curse and yell at them and move on." I was going to say the same thing...... Another option is to throw them a curve ball and and try something bigger.It has worked for me on occasion.
dont forget it is possible that the fish are feeding just under the surface if all you see is a ripple as it would be caused by their tail as the turn so maybe switching to a wet fly could change your luck
I tried this the other day on a fly fish only stream and judging by the look on everyones face either im not welcome back or they dont know what think of me