I wasn't meant to be a cook. It's a profession I accidentally fell into one summer between college semesters while looking for an easy job as a waiter. Nobody would hire me as a server, but one restaurant, in desperate need of a prep cook, told me that if I could hold a knife, I could have a job.
Sometimes even a well-rested steak will lose juices when you cut into it. Sometimes a completely un-rested steak won't spill a drop. But as a general rule, resting meat for about one-third of its total cooking time guarantees that more juices will stay inside than on your cutting board or plate.