Taxi driving is among the top professions at risk for assault, robbery, and homicide—so if you weren't sold on this career yet, that'll surely make you want to sign right up.
A lot of the danger comes from the relative anonymity of your passengers. You're required to display an identifying name and number; the customers aren't. You have to just hope that the people you pick up on the street are trustworthy. Sadly, that's sometimes not the case.
Let's also remember that you're driving a vehicle for hours a day, and sometimes at 3:00AM in the dead of snowy winter. Accidents happen, and for cabbies they may happen all too often. Car accidents are no laughing matter, so make sure you're wearing a seatbelt every second you're on the job.
In addition, taxi drivers are subjected to more mundane physical concerns. Meals eaten on-the-go usually aren't the healthiest option. A lack of physical activity can cause back pain, unhealthy weight gain, and leg problems. Just like when you're on a road trip with the fam, you should get out and stretch every once in a while.