Other than the obvious -- chicks, power, fast cars, money and chicks?
Seriously? Assuming you're not a troll -- and remember what the football coaches/drill instructors used to say about ASS-U-ME ----
Towards the last year or so of my previous career of about 17 years, I grew tired of being in a prairie dog colony of cubicles/enclosed offices staring at a computer, working nights/weekends/holidays so that we could meet a critical deadline for handoff to testing and then have the test department saunter out 4 days later and ask for the software load we just killed ourselves to get done -- plus I really enjoyed helping people and making their lives better ---
What cemented it was the day I was sitting in my kitchen after being laid off for 4 months -- (they walked in one day after lunch, said the company was downsizing, my position wasn't needed, handed me 6 weeks of severance and a box; within 2 hours, I was driving home with 6 weeks of severance pay, no job, a wife and 2 small children to feed) -- and had sent out around 200 resume's per month, received 4 responses during that time and realized that with about 10,000 engineers out there looking for work, chances were slim. I made the decision that I did not ever again want to be in a position where some bean counter would determine whether or not my family would eat based on the bottom line -- given that one of my parents survived WWII on the losing side, I knew that farmers (I don't have a green thumb) and doctors never have that problem, there's always a need ---
So coupling the two together with a propensity towards liking to figure things out -- medicine was a natural choice -- now I wish I had done it sooner -- for all the problems, all the sucky days, etc. -- my worst day as a physician is better than my best day of engineering ---
Plus the hot nurses who think the older guy who dances in the hallways singing Elvis is cute ---