I don't think you make that much in Dermatology anymore, LOL. You can work part-time, but you won't make THAT kind of money. My friend who is one sees 30 patients a day, so I also wouldn't say "you can cruise after you are out." She also has the threat of lawsuits if she misses a melanoma/skin cancer.
Like any job, it has negatives.
I"m a cardiologist and think it's alot of fun. However, I would never suggest being a doctor if you didn't really like it- 4 years college, 4 years medical school, 3-8 years training post-med school working 80-100 hours a week at $35,000 a year?? You would make more money for the hours you put in if you opened your own small business!