it contains some element of truth to it which is why the stereotype exists but when it is applied to individuals it fails.

There are obviously generational characteristics, clothing styles, musical tastes, slang, and even some behaviors, and they can be successfully applied to generations because taken broadly they're very common in whatever particular generation is being discussed. But it starts to fail on scrutiny of individuals because they are all different, some may fit some of the characteristics but not all, and some may not fit any of the characteristics other than d.o.b. and then some may be the complete cliche.

But it is our propensity to want to assign people to collectives or groups that causes these types of debates.