Playing golf with clients is one way to 'mix business with pleasure'. [=to do something enjoyable that is related to your work]
I accidentally 'mixed up' the two files. [=I put each of the files in the place where the other one should have gone]
He 'got mixed up in' a plan to destroy the government. [=he became involved in a plan to destroy the government]
(..) huh? Well, then you need to understand that it's not about glamour or money or even making a great mix cd for the o. Surgery is long, tedious and boring. Oh, I get it... Like episodes of "Entourage" (..)2010 TvShow: Scrubs Title: Our Thanks Season: 9 Episode 13