Just my $.02
I know somebody mentioned it earlier but what the heck for risk of repeating it, you're really not supposed to have grapefruit. It heightens (for lack of a better word) the effectiveness of drugs.. I know that people have people have died due to overdosing when they have just taken normal amounts of medications along with grapefruit. There's a risk with everything. *shrug
Anyway from both clinics I've been to it's been 'highly suggested' to stay away from these things: riding in an unpressurized plane, swimming in public pools (increased risk of getting MRSA, etc), tattoos and piercings due to exposure to the air and a compromised immune system, it's really suggested that you stay away from gardening/poo etc due to germs and bugs that live in there (but hey it's life not like you can avoid it completely as others have said), and a hand full of other common sense things. Stay away from sick people, blah blah blah...
There are a couple of things that I've never seen mentioned on any forums before but it's always been told to me.. 1) don't throw up. Reeeeaaaaally bad idea. Since you're nerves have been cut you can't feel if you inhale anything into your lungs. This is a great potential for infection. Coincidentally I managed to get food poisoning a year after my transplant, spent a day just tossing my cookies... 3 months later I had a growth in my lung that had to be surgically removed.. so yeah I highly suggest avoiding that one. 2) No fellatio. If you don't know what that is take caution when looking it up. Anyway this runs off the same theory of the 'don't throw up' situation. Can't feel when you inhale something, can't cough it out...
Then again as people have said this is life so we can't avoid everything, just use common sense.