DST is *not* about saving energy, that idea was abandoned in the sixties (just an urban legend now).
It is about saving lives, and improving quality of life!
A) saving lives: after the DST switch, some people now have to drive in the dark, which results in more accidents, which results in more dead. In the evening, the result is the reverse. More people drive in the evening than in the morning, so the net effect is some lives saved per day.
B) Quality of life: even though everybody complains when DST starts (and again when it ends), generally people enjoy an hour more of sunlight in the evening.
Read wikipedia for more.