In summation, simply "Murphy's Law".

Any of certain humorous axioms stating that anything that can possibly go wrong, will go wrong.

exagerated or excited agreement with what somebody has just said

Used with a repeated 'o' sound to express extreme sarcasm or blatant disregard

Course means harsh, uncomforting often refering to something or someone that is unpleasant. Its most common use is in reference to violence or anger.