The only reasons you'd drop out of highschool:
Reason 1: Your stupid as fuck. (You can get help for this too, so it's not really an excuse. You'll be better off just going through with it and trying your best, you may just make it by the minimum to be Graduated.)
Reason 2: Personal problems in your life are currently affecting you horribly and you can't cope with the problems and school at the same time.(Probally better to get help though for something like that, at least you'll get that diploma that way.)
Reason 3: Your an Underachiever.
Reason 4: Your lazy.
Reason 5: School stress you out too much.
Reason 6: Your thinking of going down the path of a criminal. (Drug dealing, joining a gang, etc.)
Reason 7: Your getting bullied at school and your scared to go anymore, because they've threatened something extremely serious. (This reason is a stupid reason, but understandable, although the wiser choice would be to report the situation to the authorities or someone that can help.)
Those are the only reasons I can think of, and if your reason is 1, 2 or 7 then you should get help for those problems. But the other reasons mean you don't deserve to even live in a country with a decent education rate and your stupid as fuck, and don't appreciate what your being given.