This Service Ontario location is a little difficult to find tucked in by the Loblaws and Pizza hut. It also looks a little run down but what isn't in the vicinity of Scarborough? I'm a Scarberian and as such I can appreciate that.
Just look for the pale green board for Service Ontario and park appropriately. I went on a Monday morning and there were plenty of tellers but also a long line to match. I was in and out in under 30 minutes when trying to update my address on my driver's license. They also do renewals here. The tellers were polite and helpful. Props to them for running a smooth ship!