I was 18, working at Menards (a home improvement big-box store like Home Depot or Lowes) and a young couple with a couple kids come by looking at floor tiles. One was a daughter who was having a tantrum, maybe age 4.

I approach them, ask if I can help them with anything. The dad says "yeah, you can take my kids."

Me, thinking on my feet, tell them I don't want to have kids for a while and say "Give me 18 years!"

I then turned ashen, realizing what I had implied, and left without saying another word. My coworker overheard and was laughing for a solid 30 minutes in front of the family.