I think everyone gets it. It's a Dream Theater fan thing - it's relatively rare to see one so it's a bit of an event when it happens, but Dream Theater fans are juuust common enough for it to happen now and then.
Although, not always a good experience. Few weeks back I had an middle-aged man come past me while I was buying some whipped cream in Lidl or something and he said in a calm, friendly, and crucially non-threatening manner something along the lines of "Don't expect to come across many Dream Theater fans here." In that instant, I panicked as I tried to work out A. what he'd just said, B. how he knew I was a Dream Theater fan, and V. how to respond - all as quickly as possible before he disappeared in a sea of frozen goods.
I rushed the whole thing and blurted out something along the lines of "CHEERS NICE TO SEE YOU HAVE GOOD TASTE AND NICE TO MEET YOU" at a shopfloor-silencing, deer-in-the-headlights kind of volume. Complete with a ravenous stare. It was like a bomb of confusion and saliva. He then said something - probably something far more polite than I deserved - and continued with his life, possibly asking himself what kind of nutters his favourite band attracts, while I shuffled gormlessly down the aisle still baffled about B.
I worked B out about half a minute later, when I looked down at my shirt and saw a Dream Theater logo.