I don't use youtube because of viruses
but I have had "you had to be there" moments.
Specifically one with my best friend. To this day, she still from time to time says "...Lápiz roto" to me.
I'll explain but hide it in these spoilers in case you guys don't care:
The other moment would be having a discussion with the same friend
with only facial expressions and mouthing words. n_n" The teacher caught me once and kept asking what I was saying.