Any of Lux's covers of metal songs. They make me laugh and they're also good. They make me laugh because one of my "best friends" is a drummer and he can't even use a double pedal and she uses the double pedal while in heels. And she's cute.
PewDiePie's videos with his girlfriend are so cute. She's just so innocent and adorable that I can't help but smile at her. I especially love Gang Beasts lol.
People make me happy. :) Specifically my boyfriend, my family, and my coworkers, but just seeing a stranger smile back at me in public is enough to make me incredibly happy. :D