You could say that Rabbi Nachman of Breslov was a Jewish self-help guru. He taught that one must avoid depression at all costs, even if it meant acting silly. Depression was distance from the Divine. Which was death to a Jew.
Breslov was a serious person. He knew the law. He starved himself, too, and regularly walked alone in the woods. His devotion was extreme and ascetic.
Still, he took the people as they were and loved them. He could handle the heavy stuff. They could not. He carried the load for them and simply asked them to feel joy in return. Joy does the rest.
Joy can be achieved through silliness. Fools feel free to be silly. Laugh, tell a joke, crack a smile.
Fools are limber. Their minds are relaxed enough to believe. Not inherently closed off, like skeptics and pessimists.
Thus Breslov wrote that fools are actually better off:
"It is better to be a fool who believes in everything than to be so clever that you do not believe in anything.
"If you believe in everything, some of your beliefs may be foolish but you will also believe in the truth.
"However, when a person is too clever and does not want to believe in anything, he may begin by ridiculing falsehood and folly but can easily end up so skeptical of everything that he even denies the truth."
- Sichot Haran #103
I am not advocating that we act silly all the time. I am simply suggesting that we not dismiss foolishness as a tactic. Sometimes it gets you closer to where you need to go.