English at it's best

Billy-no-mate An English colleague used this term to refer to poor lonely soul always having to venture out on his own without friends. Guess I am bit of a "Billy-no-mate" during my long distance walking trips.
Idempotence Property of operations in mathematics and computer science that yield the same result after the operation is applied multiple times. An idempotent element (or simply an idempotent) is something that when multiplied by (or for a function, composed with) itself, gives itself as a result. The only two real numbers which are idempotent under multiplication are 0 and 1.
YAGNI Open Source call "You Aint Gonna Need It"