The chances of you dying or being injured while working are small (flying is statistically safer than driving), but the possibility is ever-present. At any moment, an engine could malfunction and down you would go. A frightening concept, and one you’ll have to learn to wrap your head around if you want to make a career out of flight attending.
Assuming you survive, other work hazards include spilling hot coffee down the front of your shirt or getting your foot run over by a beverage cart. These two dangers are significantly less stressful than the crashing thing.
You are also spending 50+ hours a week breathing in everyone's germs, so staying healthy is also a challenge. Air travel is not an immune system's best friend.