About half an year ago, I literally fought with my DS teacher for half an hour in front of whole class,

REASON:
That dude couldn't saw the infinite while loop on his BINARY SEARCH algo hand written on board...

I mean come on dude, binary search is one of the simplest algo, and he didn't agreed with me until he dry run his written code(PS: the only thing I liked about him...HE KNOWS HOW TO DRY RUN)....

Scariest part: He was supposed to teach us trees and graphs in about a month
And it was my first day in that class