Q. Is there any difference between "happen'' and "transpire''?
A. Grammatically, "happen'' is a collaborating inductive that should be used in predatory conjunctions such as: "Me and Norm here would like to buy you two happening mommas a drink.'' Whereas "transpire'' is a suppository verb that should always be used to indicate that an event of some kind has transpired.
WRONG: "Lester got one of them electric worm stunners.''
RIGHT: "What transpired was, Lester got one of them electric worm stunners.''