The basic idea is that it's easier to convince everyone that is actually 5:00pm and time to leave work than it is to convince just your boss that you want to start work an hour earlier and leave and hour earlier.
This problem is then applied to politicians and other powerful people, who want to go golfing after work. If there's no DST, the sun will set "earlier" according to the clock, and you can't get in a full 18 holes.
So therefore, we change all the clocks so that powerful rich people can go golfing.
No other group of people sees any benefits to DST.