FUCK YES, midnight walks.
For me, it was midnight cycling. I'd bike to 7-11, grab a slurpee and western omelette sandwich and bike back. There's almost never anyone on the sidewalks, and if there was (eg drunkards on Friday night), I'd speed past them so it was no problem.
And from time to time I would go to this deserted lake shore bike path:http://maps.google.com/maps?q=hamilton+on&ie=UTF8&ll=43.277494,-79.888158&spn=0.0058
It's a place where if you scream as loud as you can, only the ducks can hear you and if you call the cops, they wouldn't get there for a very long time.
Kilometers of isolated, deserted bike path. So fucking awesome. I'm sad that I moved away.
For me, I got Graves' hyperthyroidism half way through my first year of Engineering school and started shutting myself in the dorm.
My condition wasn't diagnosed for like 3-4 years, in that time I dropped out (built up $11k debt), cut contact with my best friends, became an introvert with depression, suicidal thoughts, unstable emotions. And only went out when I needed food.