Though I'm well familiar with the putative rationale for introducing summer time, I see and experience more harm than good in what I consider a stupid attempt of the mankind to control nature.
In addition to the inconvenience of adjusting not only the conventional clocks but also our internal clock twice every year, which must have an accumulative negative effect on our physical and mental health, I recognize one problem that concerns Sabbath observance, thus may only be specific to observant Jews.
In Israel, for example, where I live, the regular Sabbath evening (= Friday evening) prayer ends even after 20:30 when the day is the longest. So observant Jews who daven according to this regular timetable have to start eating Sabbath dinner after 21:00. This can pause a serious problem not only to small children but also to adults.
This is why a number of shuls have the so-called early minyan. Before I switched to a Chabad shul last September, I used to participate in such an early minyan at the shul where I used to belong to for 16 years in Jerusalem.
Unfortunately but as expected, such an arrangement is not part of the Chabad custom. After racking my brain and consulting the rabbi of the shul, I've decided not to daven in this Chabad minyan on Friday evenings and start davening earlier by myself so that I may be able to start eating Sabbath dinner at a normal hour, by 20:00 at the latest, at least for four months between the beginning of May and the end of August.
I wish this stupid law were abolished in Israel, too, following countries such as Russia, which abolished it in 2011. I've read that Europe has also been considering to make this decision, but I don't know if any European contry has actually made it so far.
Somehow I had an impression that summer time is implemented in most countries in the world, except for those that are close enough to the Equator, thus have little benefit from summer time. But I've just found out that those countries that have legalized this twice yearly time shift are almost identical to a group of countries - US and its vassals, including EU, UK, Canada, Australia and New Zealand, but excluding Japan and South Korea. In other words, the majority of the population in the world, including China and India, doesn't have to suffer from this stupid law. Good for them!