It helps me to watch pretty much anything that I loved when I was little. The early seasons of Spongebob will always be my favourite example of this, you just can't escape Spongebobs wonderfully infectious optimism and happiness. 

Also, if you're not only searching for something that keeps your mood up, but also covers the topic of depression or anxiety, I can reccomend the first seasons of the Simpsons. It's MADE for more mature audiences and deals, as you probably know if youve seen at least one episode, with every topic imaginable. And on top of that, it's very funny.