It's actually a myth that farts are mainly composed of methane. The majority of farts are mostly composed of carbon dioxide and swallowed air, with little or no methane present. The smell of malodorous farts is due to bacteria in the gut producing sulphur containing compounds (mainly) which do smell - particularly that eggy smell!

The main smelly component in farts is hydrogen sulphide, H2S, though mixed with a lot of methane, which acts as "propellant". Basically, the body has stuff to get rid of, and some of that stuff is in gas form.

Microscopic faecal particles from the colon.

because of the decomp that takes place inside ur colon filled with bacteria

The composition of fart gas is highly variable. Most of the air we swallow, especially the oxygen component, is absorbed by the body before the gas gets into the intestines. By the time the air reaches the large intestine, most of what is left is nitrogen. Chemical reactions between stomach acid and intestinal fluids may produce carbon dioxide, which is also a component of air and a product of bacterial action. Bacteria also produce hydrogen and methane. But the relative proportions of these gases that emerge from our anal opening depend on several factors: what we ate, how much air we swallowed, what kinds of bacteria we have in our intestines, and how long we hold in the fart. The longer a fart is held in, the larger the proportion of inert nitrogen it contains, because the other gases tend to be absorbed into the bloodstream through the walls of the intestine. A nervous person who swallows a lot of air and who moves stuff through his digestive system rapidly may have a lot of oxygen in his farts, because his body didn't have time to absorb the oxygen. According to Dr. James L. A. Roth, the author of Gastrointestinal Gas (Ch. 17 in Gastroenterology, v. 4, 1976) most people (2/3 of adults) pass farts that contain no methane. If both parents are methane producers, their children have a 95% chance of being producers as well. The reason for this is apparently unknown. Some researchers suspect a genetic influence, whereas others think the ability is due to environmental factors. However, all methane in any farts comes from bacterial action and not from human cells.

i love doing really awful foul eggy farts in my girlfriend's face every morning to wake her up! never fails to make me laugh!!! i think she loves egg fart now. it's her new breakfast.

*raises hand* Yea, that would be me. Sorry. I'm a stinker *hangs head*