The madness called daylight savings

Every year a few times I have to adjust the calendar entries for people whom I work with in Europe and the USA. They save daylight in summer. I have been there a few times during this change, it makes you feel miserable for a few days when the clocks change. I ended up groggy for a week, unable to concentrate at work until I adjusted. The additional sunlight did no good as we used to have dinner while the sun was shining bright and messed up the circadian rhythm further.

What are they trying to do by saving 1 hour of daylight? My first hand experience in the majority of the first world countries that follow daylight savings is they do not care if they save anything at all. Most of the people I know use large cars (3000cc to 5000cc ones), use extensive air conditioning and heating, consume a lot of disposable items like tissues & plastics, use lots of ice cubes for any drink in any weather, large bath tubs with heated water etc. Will this one hour of not using any lightbulbs of few 100 watts going to save them a ton given their life style?