How interesting. About a week ago, I was asking that same question. I decided to explore the issue, came up with some questions and began taking a serious look at how to stop being serious. I decided to start by considering my lack of laugh from a psychological perspective first :)

Was there some buried trauma from the past that caused me to unconsciously cut off all sense of humor? I had resolved all the broken hearted miseries, having realized I was simply being asked to pay my tab for all the free sex I had received. Am I suggesting that God is some kind of ****? :) No...Well maybe. He is what he is. He doesn't Judge me, I will not judge him or her, whatever. Going further back to my childhood trauma after the flood of '64 and watching my teddy bear waving goodbye from where he was strapped to the back of a garbage truck. :( The following summer is when I began my lifelong hobby of rescuing and repairing toy from the neighborhood trashcans. I realize now how Law of attraction was working back then and still does today. In addition to kid's stuff, there are bikes, furniture, and lots of appliances. My vortex is loaded with an unending supply of televisions, microwaves, coffee makers, and an unreal supply of vacuum cleaners and George Forman Grills. :) It seems like wherever I go, wormholes jump from Dumpster to Dumpster depositing my manifestations for me to retrieve. With some cleaning and minor fixes, Craigslist and a couple trips to the flea market each month, I can cover my cost of living and occasionally follow my excitement to a nearby casino, which on a good day can get quite exciting.;)

My conclusion is that my laugh less life is not due to psychological reasons. Could it be due to the current sociological conditions? Was I exposed to an overdose of unfunny media, depressed people, pessimists with anger issues, and gloom and doom conspiracy theorists with their twisted logic. :( They think that to solve these problems, they need to inform the masses, convince them the threat is real, while spreading fear and hopelessness, all with the assumption that if you fill people with lots of fear they will have a reaction that transforms fear into courage. If you can get past the encryption, you can read the theory on this in that book "The Power of Paranoia" by what's his name. The guy who killed himself rather than be forced by aliens to reveal the names of everyone he ever mentioned the word "illuminati" to. :) My conclusion. Exposure to society and its social contructs both live and virtual puts you at 100% certainty that your laugh abilities will decline just like your hearing and vision. So rest assured, it is none of those things you mentioned. Really, "It's not your fault", Moreover. It was encouraging to learn that 100% recovery is very likely to occur under the right circumstances and exercises to revitalize and strengthen your sense of humor. I am beginning to see slight improvements. You probably did not recognize my rather poor attempt to exercise my S.O.H. during this reply, but even if you teeny tiny smiled one time, I can say I am making progress. :) Here is my plan for learning to laugh more often.

I have come to accept, embrace, and appreciate my somewhat stoic personality. This is a personal preference to refrain from overt displays of emotion. It is not that I repress or try to hide my emotions. I allow myself to choose and control how they are expressed. Laughter in my opinion is an attribute of the heart and is expressed very differently by each individual. For me a chuckle appears as a slight smile,:) quiet laughter reveals a distinct smile.:)) Laugh out load is where teeth start to appear.:O) My last question to ask myself was if I was still able to hear myself laugh. Laughter is a response to something you perceive to be funny. Think of everything hinders, interferes or other wise prevents you from the freedom to laugh as the enemy in your battle for laughter. You will need to fortify a defensive position and arm yourself will everything available for a full on attack. Your defensive armor and barricades are in put in place when you are shielded from any and all things unfunny. This includes news media and any cynical friends and relatives, and everything in your life that is of a serious nature. If you are dealing with some serious issue, schedule the time when you need to get serious with it. If you are not dealing with it at this moment, put it on the shelf and make fun of it or forget about it. I can find a way to ridicule anything in my life by imagining myself as a ghost. To summarize: As much as you are able, shield your self from that which is not funny and where that's not possible try to find something funny about it. You may even want to consider allying yourself with a young kitten, as they can be ferociously funny during every waking moment. To attack the issue head on:

Anything with funny potential no mater how much or how little or how long it can last. Long movies are generally not too helpful until after the battle is won and they can be used to help as a maintenance tool. Until you get to a place you feel good about, try to get large daily doses of fast blast funny. Google and bookmark "comedy radio online" find a station you like. They run 24/7. Listen loud or barely heard for direct or subconscious effects. I will leave you with a link that I found impossible to not laugh out loud!

http://www.youtube.com/watch?v=HttF5HVYtlQ&list=RDHttF5HVYtlQ#t=1

Get a cat!
https://www.youtube.com/watch?v=BSa4WzFNWCI https://www.youtube.com/watch?v=csD11BsSRt8 https://www.youtube.com/watch?v=kg6kULgLJJA
peace

perhaps there is a part of
you that senses what is not
consciously believed in
and it is not laughter