Go back and destroy religion.

Bring a time machine with you and teach ancient Egyptians how to use it

i'd write everything shakespeare did before he did

id give the taino a flak cannon to shoot at colombus

I want to say leave a modern computer or some other piece of technology at some point in time (maybe 50's) but I'm not sure if it could be reversed engineered

I'd love to see Socrates as modern day politician

Ending the first living cell on earth. If we are alone in the universe, preventing life from forming would do the most to change the timeline.

i'd go kill all the tiktaalik or maybe whatever the first common ancestor eukaryotes were

Avoid cocaine Limit my drinking Focus in school better instead of partying Go therapy Been patient enough to grow a meaningful relationship with someone special but I was too egoistical to see it then Learn music Workout and not gain weight from excessive drinking and eating

I'd bring a universal encyclopedia to the mesopotamians.