I have also noticed some 'tricks' used by the more successful chain establishments. Such as:
1)Tasty food - I have found that, once consuming something with anappealing flavor, I tend to attempt the same thing in the future. It seems an almost unconscious compulsion; but for the fact that I am conscious of it, and act on this impulse in a deliberate manner, it would indeed be.
2)Convenience - I have little patience available for waiting in lines. At establishments such as McDonald's, I almost never find a line. When I do, I am usually off to patronize the nearest Taco Bell.
3)Clean accomidations - Although I have heard all the urban legends about rat feces, fly larvae, ground human hands, etc. I have personally found most fast food restaurants to be quite clean. While sharing my meal with a local fly or two might be considered ecologically conscious, it is also most annoying.
4)Air conditioning/heating - This seems also to appeal to the regional homeless in many of the big cities, who often take to the fast food joints (Dunkin' Donuts, McDonald's, and so forth) when the weather becomes unpleasantly inclement. The local gourmet coffee shops, on the other hand, are rather gruff with these individuals; Starbucks is notoriously nasty in this regard. Most likely, so as not to disturb the sensibilities of the local 'left-wing activists' and student sympathizers attending the Ivy-League college next door...In any case, I enjoy eating in an environment strongly divorced from the vagarities of 'Mother Nature', and these places fit the bill.
If I avoid the fast food outlets, it is to hold my weight down; I tend to overeat, which is not an acceptable practice in my line of work. However, when I wish to indulge myself, I usually care to patronize a local Burger King, McDonald's, Taco Bell, or the Peking Gardens (a buffet serving, all you can eat waist buster that makes my mouth water to write about). In my home town, I even might speak with the locals; bums tend to be the most pleasant company when properly engaged, especially if you're buying, and they know a great deal more about local conditions than the over-educated characters up on the Hill.
My two cents, for what it's worth.