There are six basic types of humorists I believe.
Jokesters - For this group timing is everything and surprise the key. These are kings of the one-liner and the "two guys go into a bar" brand of humor. Great jokers include - Rodney Dangerfield, Bob Hope and Henny Youngman.
Storytellers - These are the folks that take a hard look at things we find serious and find the humor in it. Human foibles and awkward situations form the meat of their humor. Great storytellers include Bill Cosby, Garrison Keillor, Mark Twain, Lewis Grizzard, Justin Wilson, Patrick McManus and James Thurber as well as great comedic actors like Robin Williams, Dan Ackroyd, Danny Kaye, Tim Conway and Dom Deluise tell stories through their portrayals on screen.
Observational Humorists - These guys look for the ironies and disconnects between what we say we believe and what we actually do; between what we accept as perfectly normal and what it really looks like if you stand back a little. Great observational humorists include - Jerry Seinfeld, Gallagher, Andy Kauffman, Peter Sellers and Steve Martin. They put square pegs in round holes and show us why they don't fit and make us feel a little guilty that they don't.
Linguistic Humorists - Someone once said, "Who would pun would pick a pocket. These folks have fun playing with words. Linguistic humor includes funny poems, Limericks and puns. Some famous linguistic humorists include - Bennett Cerf, Edward Lear, Abbott and Costello, Groucho Marx and Ogden Nash
Bathroom or Anal Humorists - These folks create humor by describing out loud, what most of us do behind closed doors and wish no one ever knew we did there. The laughs come from the discomfort we feel talking about farts, people's bottoms or other naughty bits and sex. - There are few well-known bathroom humorists because as they learn their craft, most successful humorists move away from the potty-mouthed sorts of humor to something more mainstream since there's more money in it. It's a good way to get attention at first, but gets old after a while. I mean, how many times can you say the "F" word before it stops getting a laugh? Richard Pryor, Eddie Murphy, Kathy Griffin and Andrew Dice Clay started out doing some of that uncomfortable "dirty words" kind of humor. Some gradually grew out of it, notably Murphy. Some never did and their careers wax over time as audiences tire of the cheap "naughty" humor and forget they are supposed to be laughing.
Physical Humorists (clowns) - Folks who rely on physical humor use unexpected situations, pratfalls and awkward moments to mine laughter. Great physical comedians include Dick Van Dyke, Charlie Chaplin, Buster Keaton, Chevy Chase, John Cleese, Lucille Ball, The Three Stooges, The Marx Brothers and Carol Burnett. Oh, and Laurel and Hardy - forgot them (thanks Paul).
Knowing all this, however, does not guarantee that you can tell a joke or perform a pratfall so that it looks funny and not painful. I think the key element to being funny is the ability to get outside your own head and look honestly at yourself and the people around you and to not take yourself too seriously. I've never known a self-absorbed or dishonest person who was really funny - at least not deliberately so.
Humorists might be abrasive or hard to get along with, but somewhere in their core they really do realize what silly creatures we all are including themselves. All that is, except the bathroom humorists.
Those guys can be real jerks!
Just one man's opinion,