you may never die, which means that all of your friends will and you will just suffer for an eternity, always regretting that one point, that one day, that one life. as the good Doctor said "eventually you just get tired." and if The Doctor says it, it's the truth.
EDIT: on the other hand, being immortal I could just do what no one else will. step on mars? I'll live. fight in WWIII? hell no, but I would probably be drafted. on an unrelated note, this has given me inspiration for a short story that no one will ever see.