Well, I'll give most of the credit to my job, but in comparison to an average person with my size and build, yes, I'm actually absurdly strong. In some ways.
If you take a full 100lbs propane bottle, it's actually been named by it's "dry carrying volume", and is then filled no more than 80% of that volume; basically, you get 100lbs of bottle, and 80lbs of propane, for 180lbs. I can pick one up to waist height and walk around, if I need to move it. Same with rolls of granulated roofing sheet, which weigh ~85-90lbs each: I can carry one on each shoulder and take them to wherever I need them. Considering I weigh 180lbs and I'm built fairly slender, that's sort of impressive.
However, I can't bench-press the sorts of weight that are considered typical for someone of my size and build... it's simply a sort of movement I don't use at work. So in some ways, I'm certainly 'scary strong' for my size, but in a few other ways, I'm average or slightly below average.
I'm strong enough to make greenhorns get all goggle-eyed. Heh.