Everyone knows "Big Yellow Taxi" by Joni Mitchell (or...Counting Crows...or Janet Jackson). Even if you think you've never heard the song, you've definitely heard these lyrics:

Don't it always seem to go / That you don't know what you've got til it's gone?

Ugh, so true. These lyrics always make me feel sort of regretful and sad, like "yeah I had this really cool thing (sweater/boyfriend/job), but I just (gave it to my sister/broke up with him/turned it down)." Yeah, ouch.

But since regretting things is absolutely zero fun, Kanye took it upon himself to re-vamp the classic Joni Mitchell lyrics in his song, "Gone"

They claim you never know what you got 'til it's gone / I know I got it, I don't know what y'all on

Preach, Yeezy! Take it from Mr. West, if you know you've got something good...keep it! Sort of easy for him to say though, right? "Oh, oops I accidentally threw my shirt out in the crowd and I kiiind of want it back... Whatevs I'll just buy three new ones."