(2) You've probably already blown your only chance at ever finding love... hmm... I don't suppose I could go talk to my 12 year old self?
(3) I don't care if it's a waste of money otherwise, *don't* eat three full buffet meals a day at the cafeteria during college, or you'll gain 20 pounds.
(4) Okay, here, I'll lay it out for you -- if you keep going on like you otherwise would, you'll have a reasonably comfortable, reasonably boring life, where nothing much good or bad will ever happen to you. Is that what you want? ... okay, yeah, I guess it kind of is. Carry on, then.
(5) Yeah, we first make contact with aliens in '99. Where do you think we got this time-travel technology? It's the personal teleporters that I like most, though -- no more tedious mucking about with buses and elevators. I haven't managed to get up the nerve to have myself transformed into a dragon yet, but all the kids are doing it. I'd show you some of the magic spells I learned, but they don't work without the -- oh, come on, I'm telling the truth! I'm here, aren't I?