The Adventures, Mishaps and Musings of Me

Why is it always the most used verbs that are the most irregular?  For instance, "to have" and "to be" decide not to follow any logical congregation in pretty much any language (feel free to point out exceptions), and yet those are likely the two most used verbs... so why must they be obscure? 

Honestly languages, why can you not be a bit more orthodox and actually follow the grammar rules?  I would get far better marks if you did.