Who said "It's okay to be sad sometimes."?

This quote is attributed to Bing Bong.

It's okay to be sad sometimes. - Bing Bong

"It's okay to be sad sometimes."

Bing Bong

"I'm Bing Bong, Riley's imaginary friend! Nice to meet you!"

"Imagination is what makes life worth living."

"You can't fake being happy when you're really sad inside."

"Sometimes the best memories are the ones that make you laugh and cry at the same time."