For a start off night shifts are bad for your health, humans are 'designed' to sleep when it is dark, not to charge around like loons looking for people who have fallen over because “My drink was spiked”. Shiftwork can increase the risk of…
Increased likelihood of family problems, including divorce; in my case the difficulty in maintaining a relationship due to a non-understanding girlfriend.
Why do I do this again?
My skin tends to get very bad when I'm working nights, and it is on nightshifts that I'll catch coughs and colds; the stress of working unnatural hours no doubt knocks my immune system on it's arse. Unless I eat nearly constantly I'll also find myself having a general feeling of nausea throughout the night. When I do get to sleep, I'll find myself sleeping longer hours, which means less time for social contact outside of work – not very good for your mental health I would suspect.
On the positive side – if you need to put on some weight, then the diet of chips and kebab that you find yourself forced to eat (ever tried to find a salad bar that is open at three in the morning?) will soon 'pad you out'.