I recently came across the expression "warm the cockles of my heart." Of course, it's not exactly a new expression, nor am I the first to ponder its obvious implications.
However, I became curious as to what a "cockle" actually is, and looked it up. I learned that a "cockle" is a hairy plant with a purplish flower, commonly found in grain fields and on the side of the road. John Bobbit immediately came to mind at this discovery, though his anatomical mishap was not, of course, in any way connected to the word's origin. The cockle is also a type of sea creature (as in, "cockles and mussels"), which is, apparently, somewhat heart-shaped.
Invariably, this also led me to speculate on the origin of the word "cock," and found that its origin, not surprisingly, doesn't have anything to do with the heart (or the brain). The original meaning was "a male bird." The word was also used to represent aggression in connection to fighting birds. Apparently, because birds have upright posture, the word also came to mean "something that sticks up." Well, okay then.