If I had a time machine... Probably wouldn't use it b/c I'd be too afraid of screwing up the space/time continuum. Plus time travel plots give me headaches.
At which point present day you dies, then there is no future you. Then there's a paradox and all of space/time gets ripped apart and everybody dies. Do you really want that on your conscience?
I'd go back to when I chose coming back to indy and starting my career over staying in Tennessee and seeing if my relationship with my girlfriend could go somewhere and kick myself in the jewels. Not like I've had much use for them after that decision.