We love to think that Mario and Yoshi were the best of chums, but when you examine the evidence in Super Mario World, it's pretty clear that Mario was a really awful friend.
Just look at the singalong video above, from the good folks at Fox ADHD. What kind of friend would ride you around, punch you in the head repeatedly and then use you as a stepping stool to escape death? Heck, that's not even counting all the times Yoshi had to babysit Mario's dumb ass.
Stick with me Yoshi — I'll help you move, buy you lunch, and won't treat you like trash.