When my buddies and I were in late grade school, early high school, we would go to Sam Goody (shoutout to Sam Goody!) and dig through their bargain bin of CDs. This would have been late 90's. We would basically just buy all the $5 Rap CDs with crazy album artwork. This is how we learned about groups like Hi-Town DJ's, Dirty Dawg and Quad City DJs. It also likely contributed to our love of labels such as No Limit and Cash Money.
Long story short, there was a random rap album I bought by a group called Anotha Level. One of their rappers, Adolescent B Essent, performed an interlude where he is talking on the phone with his Boo, and she is giving him the business. He ends the interlude by saying "Seeeeeerious Late!" and hangs up the phone on her. My online moniker for every Fantasy Team and message board screen name since has been "Serious Late".