You are walking down the street and remenber something incredibly funny, and you want to laugh out loud, but you try to contain yourself to just smile. Sometimes try to contain the laugh is even worst.
People on the street probably think I'm crazy. I start smiling, I try to hide and start looking to my feet. It's embarrasing.
Or when I'm watching an youtube video at college (the download in faster), and there are lots of people aound trying to study, and I bite my hand trying no to laugh, but sometimes the sound just scape...and I can't even look around to see if anyone notice.

Heck that happened to me just yesterday at noon while I was chilling out on a couch at my university. I was on msn with my friend on my laptop and he sent me this vid:

http://www.youtube.com/watch?v=7RMLt28n0-M

The place where I was at was where there was a big hallway and lots of people walk by there especially between classes. When I started watching that video I couldn't stop laughing, though I never took notice of the reactions of the people around me walking by. I know it's really embarrassing to laugh when no one else is laughing, or to make yourself accidentally stand out somehow.

Another example is when I was in a lecture hall, and we had to use a program to do our homework. The girl beside me had a laptop and she was trying to install the program but she had downloaded it so it came with a keygen. She didn't know how to work the keygen and where to put the key so I helped her. This was just when the lecture started and the prof started talking so everyone piped down. Just then, the girl opened the keygen and she had not muted the sound on her laptop so SNES-like music rang through the lecture hall. She got so embarrassed and she had to pull the battery out of her laptop.

Yeah we've all been there, more than once, and it's not just necessarily laughing alone, there're tons of other ways that we sometimes accidentally stand out and it scares the crap out of us. Just act as normal as you can and try to shrug off any embarrassment.

Lol.I still don't understand why people will say that a person is crazy if he smile and laugh all by himself when on the street.Even i sometimes do such things.I remember something funny when i was walking on the street.So,i laugh..what the big deal.Besides,i am not laughing like a crazy people and not so loud too.

I've done that many times, and all you can do is bite down on the inside of your cheek and try to hold it in. It's all right if you have a laughing fit and there's another person with you, even if they don't know what the big deal is. But when you're alone, it really doesn't look good!
The worst fit I've had during my adult life was in the grocery store. I'd just finished watching a couple of new episodes of Invader ZiM, and decided to walk down the hill and pick up a few things. Invader ZiM is a very funny show, and a certain scene started replaying in my mind. I realized hat I was standing in the middle of the fruit section, staring into space and grinning ear to ear. I cleared my throat, picked up my basket and went to another aisle, and *another* scene came into my mind. This time I got the giggles and just bent over against the shelving, tee-hee-heeing into some boxes of cake mix. When I looked up, two teenage clerks were peering at me, one looking delighted and the other one worried. "I'm sorry," I said, when I got my breath. "I watched something funny on TV today, and...you know?" One laughed and the other rolled his eyes, and they left.
It's a strange idea, that laughing at nothing is so worrying. I've seen some genuinely disturbed people in both private and public places, and none of them were ever laughing!

Haha...you know wat ? i'm famous for my smile lol...most of my friend say i was always smiling along the collage corrdor and that's what make them remember my name smoothly. however sometimes i smile along my journey to somewhere some other people will look at me like some other kind >.<lll

yet still i enjoy smilling or laughing. althought i makes me looks so unserious.

Well that happens to me many times!and i can never control my laughing,well i can't help it so when my friends see me & they also start laughing(well now thats even more funny!!) i did it again just a few days back while walking on the street(just hope that the guy i looked at accidentally does'nt get any stupid ideas!!)actually i am a laughing freak!!

Yeah... i giggle to myself sometimes...just good memories lol. i dont mind if people think im crazy

I think I do.
Sometimes I will think of some interesting things,and laugh by myself。

It also happened to me many times

i remember the embarassing moments happened to me when I'm in first year, i can't really help to laugh...

also when i'm reading someting funny, i try my best to control it but i can't

then my friends will get surprise because of it, sometimes they called me "crazy"

but i'm not crazy, my brain is still going on correctly n_n

and who cares if I will laugh that loud, hahaha...

Yeah, I sometimes laugh to myself, but usually try to contain it

I often have such experiences. Nearly everyday.
Sometimes my lessons are so boring that I read fan fictions/manga chapters etc. It is quite logical that there are plenty of funny scenes. I also start to laugh in the middle of my way to school, because I can recall funny scenes of some Anime series.
Well, I only thought that I am that crazy. I am relieved that I am not the only one of my "strange habit".

Hehehe,and here I thought that only happened to me!
But hey,at least we're happy at that moment,it's not so bad,is it?
When that happens to me while walking or taking the bus somewhere,I just tone it down,but always leave a little smile on my face for a while,I feel better!
And you know what:I learned some time ago that it's better to walk with a smile than with a frown on your face!
You'll feel better,and other's will see and feel it to!
So,if I laugh or smile for some reason that appears strange to others,I just don't care anymore!
Ah,and I tend to laugh really hard when in a tense situation,just can't help it!
One time I was in an elevator with my friends,we were on our way to an exam,and everyone was so stressed that they didn't say a word!I just bursted out laughing!They looked at me like I was crazy at first,but then started laughing as well!Not a bad way to go to an exam,is it?They were a bit more relaxed too(until we started the exam at least...)!
And when I'm studying,when I don't understand something and I've been at it for so long,I start to get desperate,and I just laugh,but that kind of laugh that really makes people think that you're crazy...and I usually study in a cafe so you can imagine the result...ahahah!

I thought only I did that!
I don't laugh in the middle of the street OFTEN, but when I do, it's always coincidentally at the WORST times. Because I live in the suburbs, I only really walk in the street whenever I go to the city, but every time I go, it happens... oh well, life goes on, right?

It does happen to me, not too often though.
but yeah ... i will laugh alone in the street if i remember something very funny. when i'm in a class ... i try not to laugh ... if i can't hold it ... i will ask permission to go outside a class then laugh all i want outside ... .

I laugh when I want to, damnit! Screw all those around me, I don't give a damn what they think of me. As long as I, myself don't feel any embarrassment then what does it matter? Walk tall, walk proud, and everyone will be the fool.