An ion walks into a bar and says 'I think I left an electron here last night,' and the bartender says 'are you positive?'
Madness string 3024
I think my best advice on staying positive is to talk to people who make you laugh or smile. There's a lot of research on this, and I have personally experienced that laughing makes you happier. Being around people who make you feel good is good. I know it sounds obvious, but sometimes people forget.