I sing along a lot, but tbh, I never really learn the actual lyrics so I just sing along with what I think the lyrics are. This can include singing along using words which don't actually exist, or with words that do exist but which just wouldn't go together.
I used to do it all the time. (In people's presence, or alone.) Now I rarely even play music in front of other people. For the sole reason of not going into a "what the hell is this noise?" argument.
Now I just nod my head if I am deeply in a music appreciative moment.
At work (grocery store) people always sing along their own versions (usually sexually explicit) of the lyrics to the shitty pop/country songs they play on the PA system
I sing along when alone, my aunt and the rest of the family here is fucked up enough I don't need to provoke the situation, i like not sleeping in an alley.
I sing along to everything, be it Japanese sludge metal, neo-classical shred, or brutal death metal. My vocal chords usually hate me at the end of the day.
I got some weird looks the other week, walking back from a mate's flat at one in the morning, pissed up and swaying with cigarette in mouth, while screaming along to Pantera 'Fucking Hostile'.
I got some weird looks, some cheers and 3 sets of horns for doing that totally shittered on the bus, except it was some destroyer 666 blasting from my headphones.
come out. drink, chill, listen to metal and generally have a mini RC fest involving NAD, Lurch, MFJ (hopefully), maren, maren's friend pam, my buddy ryan, and perhaps a few others who i won't announce until they are confirmed.