For me, oddly, it's teachers.

The reason: Great profession, but our schedules just aren't compatible. My work tends to get busiest mid-late summer and stays that way until year's end. I prefer traveling during non-peak travel times and non-school vacation weeks to avoid crowds and higher travel costs, such as early autumn or spring (occasionally, I'll do a summer trip, but only if it's for an event like a music festival.) I've also noticed that teachers go absolutely HAM during the summertime in going to the beach and going out all of the time with no regard to the fact that those around them don't have the convenience to take that much time off so leisurely. Come the school year, they're typically in bed very early -- like 8-9pm -- and they always seem to want to meet up for dates really early, like 4pm or 5pm when I'm still not completely out of work yet. They also look at me like I have two heads when they discover that their pace of life isn't the norm for everyone.

Runner up: anyone who works on the weekend (nurses/doctors, anyone involved in the wedding industry, sometimes social workers, and restaurant workers.)

Second runner up: I work in the corporate world, but anyone in the corporate world whose entire personality is their job and has a habit of signing back onto work at night/weekends because they prioritize work over everything probably isn't a great sign.

I'm wondering if others find similar patterns out there with certain professions? What are you least compatible professions?