Meaning

Mecheieh:
pronounced, meh-KHY-eh

It's a pleasure! That's what mecheieh means. The word is often used to express relief from human misery. A man walking around a subway station looking for a men's room for a week-and-a-half. When he finally finds one, "Oy, a mecheieh."

It's used when you find a fresh roll under a basket of stale ones. Or your umbrella finally opens in the rain. Or your mother-in-law stops talking for five seconds.
If a guy is sweating in 90-degree weather, and walks into an air-conditioned room when he wasn't expecting it, immediately every Jew will say the same thing, "Oy, a mecheieh!"
They talk to the room.

A mecheieh is something that's such a pleasure you don't have to have a person in front of you to tell it to. When a Jew says, 'a mecheieh," there's likely to be no one else there. The pleasures are something that he can't wait to bless and he can't wait for anybody to listen to.