To begin, let’s separate the term “dihedral effect” from “actual dihedral”. Dihedral effect is simply the tendency of an airplane to roll away from a sideslip. Whether a particular wing will provide that tendency depends on several other factors besides actual (physical) dihedral. Generally a high wing with no actual dihedral will exhibit some degree of dihedral effect. The amount depends on such things as height of the rudder, amount of sweep, if any, distribution of the fuselage side area, vertical location of the cg, to name a few. If a particular airplane has some dihedral effect with a flat wing, a little anhedral can eliminate it. A little more anhedral will make the aircraft roll into a sideslip, which is not generally desirable.

For general sport flying, a little dihedral effect is desirable because the airplane is laterally stable and is easier to fly. However for aerobatic flight, involving sideslips (such as knife-edge) it is not desired because it requires coordination with aileron to maintain position. It is referred to as “roll coupling” in that case. The amount of dihedral effect desired or not is a matter of personal preference. Lack of it requires more attention to fly, and pretty quick thumbs, while a little dihedral provides a more relaxing and sedate airplane.