I always forget daylight saving time in Europe and this is happened this time also. I have knocked the door of my colleague one hour before the scheduled time today for going to office and he remembered me that we have one more hour to sleep, so relax.
DST is most commonly used in temperate regions, due to the considerable variation in the amount of daylight versus darkness across the seasons in those regions.
Governments often tout it as an energy conservation measure, on the grounds that it allows more effective use of natural sunlight resource in summer time. Since there is less darkness in the "waking day", there is less use of electric lights. Some opponents reject this argument also.