Until just a few months ago, right before turning 21, I thought that the slogan for Kay's Jewelers was just extremely fucking retarded.
"Every Kiss begins with K(ay)." I had never seen it on paper before, and it isn't a phrase, so I never, in my entire life, realized that it is just a really stupid pun. Every kiss literally begins with the letter K, and not Kay.
I truly believed that the fifty+ different commercials that I had seen thousands of times in my life were all saying that every kiss began specifically with their jewelry, and I despised them for having such a stupid slogan. And then it finally clicked at age twenty. Boy did I feel stupid.