Foggy stalks Karen when he decides she's acting weird. Nobody can tell me Foggy hasn't thought the same thing about Matt before, but I pinged on this specifically when Foggy knows to find Matt at Fogwell's. Foggy tells Matt he's known about him going there for a while but he doesn't explain why or how.

Has Foggy followed Matt to the gym before? When, how often, and how is it Matt didn't sense Foggy trailing him?