Who Sings at the 7 Eleven?

One more thing...

I'm pretty friendly with the 7 Eleven people (I'm a very loyal customer). So today, one of the especially friendly workers was on the side of the register and the older man (like... 45-50) was doing the actual register. Now the people that work there are from another country... I'm not sure where, but I imagine they are middle eastern. So the younger guy tells me something that sounds either like "he's single" or "he's a singer." I asked him to repeat it, but the older guy told me the same thing... either "I'm single" or "I'm a singer." So I just smiled and said "yeah?" although I was a little worried that the younger guy was trying to set me up with a middle-aged man. But then the guy says what I ASSUME is "Yeah, I love to sing. I think everyone should sing." At this point I'm pretty confident that he's talking about singing because it would make no sense if the word was "single." So I respond, "Yeah, me too." And the guy goes, "I know."

How does he know I like to sing? Have I been unintentionally singing in the 7 Eleven? Mysterious.