I have personally expereinced the "sticking flap switch" (40 degrees flaps) on a C150 when doing a touch and go. The aircraft got off the ground all right but wouldn't climb. My instructor did a 180 turn around a gum tree and we landed. Problem could not be duplicated on the ground.
Lesson: Make sure the flaps are coming up on a touch and go. Be aware that a touch and go on a short gravel strip is going to be terminal if the flaps don't retract.
I think this may be why Cessna limited flap travel to 30 degrees.
On a related matter - assymetric flap extension (or retraction) be aware that it can happen. Large aircraft have a flap assymetry switch that will stop flap movement if it is not exactly synchronised.
Some people in light aircraft don't select flap while turning just so they can detect assymetry if it occurs.