And while not every surname we know today originated as someone's occupation, quite a few did. The most common surname in the English-speaking world, Smith, came from anyone who worked with metals–blacksmith, silversmith, coppersmith. And since the occupation of working with metals goes all the way back to the Bronze Age, it's no wonder that there are so many people with this name.
Other common occupations from which surnames arose include: clerk, from which came the name Clark; bricklayer, from which came Mason; ropemaker, from which came Roper; doorkeeper, from which came Porter; and tanner, from which directly came Tanner. Some names, like Schumacher, from the German for shoemaker, Farrier, from the French for blacksmith, and Chiffonier, also from the French for wigmaker, evolved from their linguistic roots.
Some are close to their occupational origin like Bailey or Bailie, which evolved from bailiff, or Baxter, from baker, Draper, from dry goods dealer, or Bowers, from bowmaker. A variation on the latter is Fletcher, also a maker of bows and arrows.
Other names are so far removed from their original occupations that it's hard to tell just what the person originally did. The common name of Fuller, for example, came from a person who cleans and finishes cloth. Another is Hayward, a keeper of fences. It's likely that a very well known celebrity, Mick Jagger, doesn't know that one of his ancestors was a fish peddler. Boy, has he come a long way.
One of Daniel Webster's ancestor's was a loom maker while one of former British Prime Minister Margaret Thatcher's relatives was a roofer. And all the Brewsters in New England are probably descended from a brewmaster.
Knowing the origin of a name can lead to clues about a person's ancestors. While some people, like blacksmiths, performed their duties just about everywhere. Others were location specific, such as those with the names of Longshore, from longshoreman, a dock worker, and Cooper, barrel maker, both of whom would have lived and worked near the water, or Tasker or Hooker, both reapers, or Yeoman, a farmer, all of whom would have worked on farms inland.
To get an idea of what occupations your ancestors might have had, check out Last Names Meanings Dictionary, or Ancestor Search - Genealogy Search Engines.