I have observed houseflies for many, many years. I have watched them soar onto my arm. I have seen them land inside my mug of water. I've had to wipe my glasses -- on more than one occasion -- after a housefly absent-mindedly sailed right into one of the lenses, leaving unpleasant fly residue behind.
So, based on my experiences with houseflies, I can only come to one conclusion: They have no idea what they're doing.
The typical housefly is gifted with the amazing ability of flight, and its life span is only a few weeks. If that were my lot in life, I would make the most of my time on this Earth. I'd leave the nest at the age of 5 or 6 (days), travel the country, fall in love, marry, start a family, have 500 or 600 kids, raise them to adulthood, and then finally go on that second honeymoon with my wife that we'd been talking about for so long.
This is not at all how the typical housefly chooses to live its life, though. The typical housefly drifts aimlessly, from one trash can to the next, from one dirty plate to the next, from one human's face to the next. It is without direction.
Literally, the housefly is without direction. You've seen the housefly in action. It simply refuses to fly in a straight line. Instead, it zags, then zags, and then zigs and zags and zigs and zags and zigs and zags and...I'm not sure it ever ends. Its travel itinerary is basically one very long and confusing connect-the-dot puzzle.
I would love to be a fly on the wall when one fly asks another for directions. "I hear there's fresh dog poop on Main and Thompson. Do you know how to get there?" "Oh, it's less than a block away. Let me look this up on my GPS for you....OK, head south on Henry. After three feet, turn left. After six feet, turn right. After two inches, turn left, then stay in the right lane. Fly straight for a good 23 feet. Then, turn right onto Main. After two inches, turn left, then turn right. Land on the ground and stumble around for a bit. Resume flying west toward Thompson. After two feet, you'll have reached your destination."
Had they researched this on Google Maps and printed out the instructions, it would have taken three pages, at least. That's a lot of pages for a fly to carry around.
If only I could sit down with the housefly and explain to it how fortunate it is to have a talent that not many other organisms have. I would tell it, "What you have is rare and special. Don't waste it by hovering over garbage, or by smacking into my glasses. Spread your wings and fly. Fly anywhere you'd like. The sky's the limit.
"I should warn you, though, that if you happen to land in a bowl of soup and drown, humans will crack jokes at your expense. So be careful out there."
I'll leave you with this thought: Did we really need two photos of houseflies mating on the Wikipedia page for the housefly?