Is it normal to just randomly stare off into space without thinking?

Sometimes, and it happens more often when I'm tired, my train of thought will not derail but STOP entirely, and I'll be left staring wide-eyed into the distance. My little sister says it looks as if I've seen a ghost.

When this happens, I am aware. It's not like "and then I woke up a few minutes later"--i can tell time is passing, I can hear others, it's just like my brain has decided that it's clocked out. Sometimes after it starts I do start thinking about the fact that I'm staring into space, but it's not necessarily something I want to stop doing. It's kind of calming in a weird way.

Often I'm broken out of it by someone saying something about it, or laughing. Usually in total it happens like 10-30 seconds at a time.

I didn't think it was absence seizures because it seems like those are more serious and leave you unaware until the moment you pull out of it.

Is this just a stupid habit I've picked up?