verbs - 自～／他～ペア：逆の形 -- Transitive/Intransitive pairs: opposite forms

I've noticed (through much frustration) that many 自～／他～ pairs have "opposite" forms; particularly with the ~u and ~eru types. For example, 焼く・焼ける are opposite from 開く・開ける.

焼く　（他）　－　パンを焼く ("Bake bread")
焼ける　（自）－　パンがちょうどよく焼けた ("The bread was baked just right")

開く　（自）　－　ドアがひとりでに開いた！怖いでしょう！ ("The door opened by itself! Isn't that creepy?")
開ける　（他）－　彼女のためにドアを開けてあげる ("I open doors for my girlfriend")

Is there any logical reason that some pairs like these have "opposite" forms??? Or is it just to piss off the people trying to learn them??