Let's just say you go back in your time machine to the 15th century.
All you need to get famous like Leonardo da Vinci is this information, printed on your T-shirt:
Dude, ...if i'm going back in time, ...it sure as heck won't be back to the start of the transatlantic slave trade!
I might want to check out Ancient Egypt, during the time of the building of the Great Sphinx.
I'm talking thousands upon thousands of years ago when the Sahara was a vast fertile savannah.
Of course I'd want to be part of the priviledged class. Don't know how I'd fare without running water.