OB is ridiculously stressful, in an antagonistic kind of way.
1. A good subset of patients have wildly unrealistic ideas about pregnancy and delivery, and when their ideas meet reality it's not always reality that wins.
1.B. You will be the target of their ire whenever their desires are not fulfilled, because patients seem to think docs are actually in charge of something at the hospital. We usually are not.
2. It's wildly litigious. Their child was perfect (in their imagination) before being born; then you got involved, and now their child is not perfect. You must have fucked something up in the delivery and ruined the perfection of their child.
3. Way too much family involvement. When you're doing surgery, you're usually dealing with a patient's attempts to understand what's going on. When you're doing OB, you're dealing with the patient, the husband, the mother, mother-in-law, etc. Each person will come up with their own distorted vision of how things should be, and when it doesn't align with reality, the doctor is an idiot who doesn't know what they're doing. (Doctors are not perfect - just people - but it seems like every single person without medical training seems better equipped to identify the proper medical course of action than a physician is.)
4. Lots and lots of on-call time. Lots of unexpected interruptions and lots of drop-everything-and-drive-to-the-hospital.
5. There used to be good money in it. There isn't now, which makes all of the above grate on one's nerves.
The results of the above really add up to demolishing the spirit of OB/GYNs. Points 1-3 really make you feel like you're persistently at war with patients, which is the worst feeling ever. I've never been on anyone's side but the patient's, and having them treat me like an enemy ruins my job, and ruins my ability to do my job.
I ultimately chose to pursue a niche thing that shares a name with an existing medical specialty, but is a distinct niche. I can't really identify it without doxing myself, so forgive me for not.