~ I set my mouse sensitivity to 'HYPERSPEED!!!' and then forgot how to change to back to normal. I only found out 2 months later.
~ I tried swimming in lava in iron boots, thinking that I would float.
~ I made a 1*2 nether portal. I was annoyed.
~ I know this may be usual for new players, but I broke diamond ore with a stone pickaxe.
~ I tried leashing a creeper. You know what happened next.
~ I went past an Enchantened Golden Apple in a mineshaft *facepalm*
~ I killed a villager right in front of an Iron Golem. Oof.
~ I tried placing a minecart onto stone. Took me a week to understand why it didn't work.
That's all I remember.