- The university sets a schedule and you are assigned to classes that are otherwise short staffed - there's little consideration for your interests. Basically you get bottom of the barrel courses and inconvenient hours.
- The students can barely program and do not care. I know it's a cliche, but it can't be understated. These "masters" students could not handle the equivalent of leetcode easy problems. Get ready for a lot of late submissions, half-assed homework, and begging for extra credit. Oh, and the final is open-book and you're not allowed to fail anyone.
- The student body is largely H1B visa holders. Anyone that's been paying attention to the H1B story knows that part of the visa scheme is funneling students into masters programs to improve their chances in the lottery. Nothing against visa holders, but this is obviously a cash cow for universities.
- Academic personalities and elitism. You are an outsider and will be looked down on. In my friends case, the Dean started getting very bossy and started dumping responsibilities on him that he really had no business being apart of. Ex. Being a judge for someone's thesis defense. My friend got a lot of satisfaction out of submitting his resignation after just 2 semesters.
I personally have a fondness towards teaching as well and tend to romanticize it, but my friends story really turned me off to any interest in that line of work. Of course this is just my friends anecdata, YMMV.
At my university, my favorite professor’s title was “senior lecturer” because he only had a bachelors. This was despite being a Times bestselling author. (He taught literature and writing.)
Your job title probably won't be 'professor', but you'll be doing basically the same work as one.
As a former graduate student myself, I'm actually not aware of any non-PhDs who are adjuct faculty or community college instructors. I'm not claiming that they don't exist anywhere, but given the number of PhDs and the number of available academic jobs, the competition is fierce, and non-PhD candidates are likely to lose out to PhD candidates.