re: $10 endless apps at TGIFridays. What is the catch?

You get full. When I worked at On The Border we had endless enchiladas and most people, even the fat asses, couldn't eat more than 3 plates or so. Most usually wouldn't even get seconds.

Also its a loss leader to get you to buy higher margin items like drinks. They don't give a shite if the whole table only gets one $10 endless app order if they are all buying drinks consistently.