What's the sneakiest cash-shop trick in MMO land?

Casino chain Harrah's could teach MMO cash shops a thing or two. The casino famously employs a complicated system of tracking and metrics to estimate when precisely an individual losing player will walk away from a gambling game... and right before that predicted moment arrives, employees swoop in with complimentary food and free currency to encourage the loser to stick around (and lose more, of course).

I don't know of any MMOs that use this exact trick, but they certainly could. An MMO could easily track how many mobs you're willing to kill for a drop or how many lockboxes you're willing to buy before you stop playing and stop buying altogether, then trigger a drop custom-tailored for you just to keep you around. The thought of it is a little creepy but not entirely unwelcome after all the Dragon Chests I've opened to no avail lately.

That day is not yet upon us, so today, we're wondering just what is the sneakiest cash-shop trick in MMO land?

TH