I was going to post this also!
I have a bunch of LED work lights for the garage, also head lamps on a strap (those are a game changer for working on the car). The lights themselves are amazing in terms of brightness and (to a slightly lesser extent) how long they run, but user interfaces are super annoying. I haven't figured out how any of them work because they are all different, and I keep bouncing between them depending on what light I need. I just mash buttons until I finally stumble on what works. Some have a color temperature setting (cool/warm) in addition to brightness, then there are also flashing modes on some lights. It is really annoying to click through them -- usually you can't know you are already on the brightest setting until you click past it -- so then you need to take another "lap" around the modes..
Let's not forget the battery charging indicators on those lights that also vary wildly. The "no brainer" charging indicator approach would be to have a simple red (battery low) / yellow (partially charged) / green (fully charged) indicator, but that is
NEVER the case. On some, a green LED mean it's charged, on others green means it's charging, and sometimes the status LED being off means it's charged -- sometimes red means it's being charged, on others it means it's fully charged, and sometimes red means it's discharged. There oughta be a law demanding uniformity on user interfaces!