When I was in 5th grade, our teacher (who to this day is one of my favorite I’ve had) filled out end of the year individual memory pages for each of us. I remember on mine, he wrote “you have the rare ability to balance seriousness with sillyness, which is unique and amazing quality. Never lose this." 

15 years later, I still think back to that compliment and advice, and I still strive to maintain that balance :)