I think its basic human nature to join something and "get involved" especially if its related to something you like doing such as travel or even just flying.

Then there is the routine - check your miles, check your tier points, check your online booking, check your seat, check flyertalk, check reward availability....sometimes its frustrating and sometimes is absorbing - a bit like life in general.

Perhaps FF programmes and everything that goes with them only really appeal to those with a borderline obsessive compulsive disorder...

Like everyone here