My worst guests have been seniors, hands down. They either don't fully understand how AirBNB works/what to expect from it, or think they're still going to get the exact same level of service they would at a hotel (like expecting me to be their personal concierge, not reading anything in my binder, calling me to ask where they should eat dinner, etc.)
The most ornery guest I ever hosted was an older couple who:
1) Put in the wrong address in their GPS as they 'couldn't find my home' and repeatedly called me asking for directions. When I'd ask 'Okay, where are you now?' they couldn't even tell me. I spent 25 minutes on the phone with them, directing them in real-time to my home, despite them repeatedly missing turns or saying things like 'I don't think I can turn left here'. (They weren't used to big city traffic, to their credit.)
2) After I spent 25 minutes on the phone with them and buzzed them into the parking garage, I monitored the August door lock to make sure they'd gotten into my condo. After another 20 minutes with nobody opening the door, I called back to ask if everything was okay. The gentleman was FUMING. He was upset because my owned parking space was next to a retaining wall. 'How the **** am I supposed to get out of my car?!" he demanded. Literally nobody else has ever complained about this, nor has it been an issue...I was stunned. I suggested if he didn't feel comfortable opening his door adjacent to a wall, to pull back out and back the car in? He yelled 'NEVER AGAIN! Never again will I get an AirBNB!" before hanging up on me. He was over it and he hadn't even entered my condo yet! Haha
3) The guest book entry they made complained about the Toronto traffic, no trolley for their luggage, no hard-wired main phone line (does anyone have those anymore?) and no grab bar in the shower.
They never left a review, thank god. The amount of time I spent making sure they were okay was ridiculous. I'm always a little terrified now when older guests book!