Here’s a horse fly (family Tabanidae). It seems to have an injured wing. That’s because I smacked it. I hate these things (as would anyone, if they were ever bitten by one), plus it wouldn’t hold still for the photo.
I’m pretty sure the Tabanidae are my most-hated insect family. Mosquitoes (family Culicidae) are a more persistent annoyance, but I’d gladly take twenty mosquito bites to one horse fly bite. They really hurt. Horse flies are among the world’s largest true flies (order Diptera), and they have the slicing mouthparts to match.
On top of that, deer flies (also in the Tabanidae) combine the worst aspects of both mosquitoes and horse flies: they’re persistent, annoying little buggers, plus their bites are painful (though not as painful as horse flies.)