In downtown Toronto, I've always associated TH's with homeless people. Especially between 10pm and 8am they're dominated by groups of urine-drenched homeless types of all backgrounds. Early mornings - 5-7am - you'll see construction workers; a bit later - 8-10am old men from any cultural background - Chinese, Filipino (my Filipino co-workers especially loved Tim's, perhaps because their countrymen typically are the TFWs working there?), Jamaican, and yes old white men, especially seen in small town Ontario; lunch time you'll see new Canadians with large families having an affordable meal away from home. Smokers love Timmys: they often congregate outside. Cops are always stopping by. Back in the days I went to Tim Hortons, it was always at a location at a subway station - eg Islington - around 6am to get a Jalapeno breakfast bagel (although I eventually learned the mom and pop bakery at Islington Stn had better donuts and coffee.)
Coffee Crime seemed to occupy a niche several steps down - taxi drivers, hookers, drug dealers; worst of all the donut chains was Galaxy Donuts - in the 1990s that meant the mentally ill from CAMH, homeless First Nations, crack whores with locations on Queen West, Ossington and Dundas and Keele.
If you want a fantastic donut, go to Parkdale's Glory Hole.