Coaches whistle while they work. Cocktail waitresses serve highballs. Collectors do it in sets. Combinatorialists do it a countable number of times, sadly. Combinatorialists do it discreetly.
Comedians do it for laughs.
Communists do it without class Computer Game Players just can't stop. Computer operators get the most out of their software. Computer programmers do it logically. Computer scientists do it all night long. Computer scientists do it by bit.