Because ear wax (technical name is cerumen) is supposed to repel insects, bacteria and water. It is made of various oils that are secreted from glands in your ear. These mix with dust and dead skin and form ear wax. Wax has a natural flow to the tympanic membrane (Ear Drum) and then migrates out of your ear. This natural migration helps to keep the ear canal clean. Fresh wax is a golden brown colour but as it gets older it gets darker (I look in peoples ears {and test them} for a living, and frequently see compacted black ear wax). When people stick things in their ears to clear wax it often impedes the natural flow and pushes wax further into the ear -causing a build up. So never put anything (including cotton buds) into your ear that was not designed to go there.
You get used to it - and I am getting paid for it - there are worse jobs - Suppurating discharging ears though - they do make me feel sick - the smell is awful