I have this issue that occasionally embarrasses me in public. Sometimes, I don't know why, funny things will randomly hit me in that laugh-so-hard-you-cry kind of way. I don't think there's anything wrong with that in and of itself, I quite enjoy laughing that hard. If I'm by myself, no problem. If everyone else is laughing that hard, no problem. But not infrequently it happens to me and nobody else. It's so embarrassing.
Like the other night I was hanging out at a restaurant with a group of people that included a couple and their little baby. The baby got passed to one of my friends and all was well and good and cute. Then my friend casually took a swig from his beer bottle, set it back down, and looked a little alarmed and used his sleeve to wipe off the top of the baby's head. Me and one other person saw this and while she definitely laughed, I couldn't stop laughing and had to forcibly choke down the rest of my laughter. I also couldn't look at that friend holding the baby for a good 10 minutes before I finally really calmed down.
Also recently, I was recounting to a friend the scene from The Wedding Singer where Drew Barrymore's character gets drunk in a bar and pukes. She comes out from the bathroom and says to Adam Sandler's character, "I vomited in my hair. Does my hair smell like vomit?" For whatever reason, I could not say those lines without laughing. Particularly the word "vomited." Even now I just said it aloud to myself and it's making me laugh. I can't tell you why it's so funny.
One time a few years back, I was hanging out with friends at someone's apartment and one of the guys was talking about his recent trip to NYC. He mentioned going to a concert and another friend, who happens to be Australian, asked "Oh, was it a pianist?" And I knew what he said, but I couldn't help hearing something else, and it just made me giggle. A couple of other people giggled too, but while they all stopped giggling, I couldn't stop.
I know that I get this from my mom. It happens to her too. But the great thing is that if it happens to her while I'm around (or vice versa) I start laughing uncontrollably just because she is. And then she starts laughing harder because I'm laughing too and we just lose it completely. This is great because it's not embarrassing when it's not just me. Instead, it feels like we have some completely hilarious inside joke that no one else gets. Though even still, sometimes she calms down way before I do.
Just for the sake of another example, this video always makes me laugh that hard: