Here I'll explain some inside jokes for the fun of it :)

I'll categorize them with the person I made them with.

Best

Blaming Bellatrix

So I don't really remember why we started blaming her. But we do. It's our thing. I remember the first thing we ever blamed her for was for global warming, and it exploded from there. No offense intended, you Death Eaters can blame Arthur all you like...We all know who's to blame ;D

Yupo

So yupo is basically just a typo Best made. She meant to say yupp, but she said yupo. I decided it was the new spelling of the word. We still use it in everyday conversation....