A term I use to bid farewell to someone who is going to have a week off of work or school.

It basically means goodbye forever. If you say this to another individual, you are telling them, from now on, from this moment on, you couldn't care less what happens to them, as long as you never see, or hear from them again. You are banishing them from your circle of loved ones and friends, from your life. It is almost always justified/warranted.

the catchphrase used by mick foley's late 90's persona mankind

It is understandable, so you may have a nice day; even if you didn't get your ice cream from McDonalds.

When a girl says you have nice hands she wants you to finger her.

When you are talking to someone who is cooking food that smells nice.

When a friend is the literal reason, in every scenario, as to why you can't have nice things. (Ex: always spilling beers, falling over things, breaking things, etc.)