I'd make a sweet mansion in space, invite all my friends who are struggling in life. Fill it with secret passageways and magic items n stuff too. I'd retcon history to make me be seven feet tall, instead of 5'6". Probably travel back in time to several thousand years ago and make one random person immortal for the hell of it.
I mean, I wouldn't want to mess around with humanity too much. I wouldn't want to prove I exist, and I wouldn't want to ruin people's lives with my shenanigans. If anything, I'd create a miniature simulated world, where nobody in it is actually "real" that i can mess around with all I want without feeling bad. Like a sandbox.
Then I'd unleash all kinds of supernatural stuff on them to see how they react. Make people invisible or huge or tiny or create weird magical pocket dimensions full of magical items and monsters... ya know?
drown all of humanity in a massive and spontaneous chocolate pudding flood and spare only the annoying tumblerinas, who i would then watch from above and laugh my ass of as they die from there own incompetence, that or force them to kill each other for a seat in godhood, which of course would be a lie... i would just zap the lone survivor with lighting!
make the fucking deviantArt chatroom operational on all browsers for all devianTarts. its been down since fall last year. it is sooo bad people are forced off the site (to places like discord) what a mess.
I'd make the nature around my place full of more pretty colors, there's too much green and brown over here Also, can't ever go wrong with some petty jacking with mortals. Replace their car's oil with Coke and then change it back only after getting someone to look at it.