My husband used to not laugh out loud, he'd just shake his shoulders. For the longest time I fought with every conversation to get beyond the silent shudder. I, on the other hand, rarely restrain a laugh...and, I've been told it's loud and occasionally resembles a hen cackling (get the picture, could be annoying). I'm grateful for those who say, after a fit of loud laughter, that they appreciate the noisy intrusion; likewise, I'm grateful to my family for routinely picking on my laugh (in my defense, I believe it's genetic so I can't help it) to keep me concious of it's potential power for aggravating even the most long-suffering of individuals.
Over my life I've attempted to vary my laugh with limited success. In high school I arbitrarily decided my laugh did not suit me (it was too low) so I would change it. So, I went in the other direction. What I ended up with was a hodge-podge of noises that do sound a bit like a cackle in various octaves and always in crescendo. Moral of the story: enjoy what you've got.
Recently, I played with the idea of developing a work laugh. When I discovered my Myers-Briggs to be INTJ and another interpretation suggested that made me a "mastermind", I floated the idea (with some approval from a friend) of starting a "muahahahaha" laugh. Unfortunately, I'm guessing that would creep out those around me and potentially limit any sort of professional advancement.
Another time I attempted to smother my laugh when the possibility of someone hearing it would result in an unpleasant meeting (we were not laughing at the individual in question, just didn't want to particularly run into him). It was horrible and only induced further laughing. I believe it may have produced a snort after a high-pitched series of giggle-bursts. Horrible.
I am also fairly liberal with my laughing and sometimes induldge without a reason apparent to anyone else. Recently I laughed after a co-worker invited me to lunch. It wasn't a funny place to go, but I laughed. Another co-worker rightfully asked for clarification; it was simply that the destination seemed atypical to anywhere I'd heard them dining before. In my head, it was amusing. But, no one is in my head to clarify to others. This could be problematic.
All this to say that laughing is a pretty important part of my day, and I've started to appreciate the various kinds of laughing that take place (even if not as boistrous as my own). This is not meant to be a reinvention of Mary Poppins, but there are cluckers, blurters, snorters, shakers (not the religous group), head-bangers, knee-slappers, hissers (that's a Mary Poppins reference) and gigglers. Without a doubt my favorite are snorters and blurters. They just make you want to laugh more.
I don't think all of life is funny. I do think when those moments are available they should be appreciated...in whatever form that takes. And, if you're on a long road trip by yourself and need something to do, then fake laughing can be great entertainment (for the other people on the road who will pass you and think you're nuts...not that I would know).