How could a waiter be so dense?
It’s not always the guests who ruin the atmosphere for Valentine’s Day dinners. In this case, it was a super-dense waiter with impeccably bad timing. A few decades ago, the OP’s dad was proposing to his mother at a restaurant. But one waiter decided that that was the perfect time for him to show up.
In the middle of his proposal, the waiter comes and interrupts the man’s speech. The man was angry beyond words, and his mother just stared blankly at the clueless waiter. Worst of all, according to the OP, the waiter didn’t even realize he did anything wrong!