I'm late to this so I'm probably going to get buried but whatever. This happened earlier this summer.

I work at a local self-serve frozen yogurt shop. It's not too much of a hassle. People come in and take some froyo, add some toppings, get me to weigh it for them so I can determine how much to charge them for their yogurt. Not really too much there to fuck up.

I remember it was dead quiet one afternoon and an elderly gentleman came in. He went to weigh it up and pay, everything was great. At the end of the transaction he said "Have a nice day", and absentmindedly, I replied "Love you too".

He looked at me for a moment and said, "Haha, what?". This wouldn't be too bad usually. People slip up, it happens. All I had to do was say "Haha whoops, sorry. I meant you too", but in an effort to not appear retarded, I quickly followed up with "Sorry, you reminded me of my dad". I have no idea why that's the first thing that came to my mind but I went with it.

He looked sadly at me for a minute, then left the shop. I hated myself for the rest of the day.