For me its the ‘Knock Code’ that LG had on their phones (I really wish LG still made at least the V series phones)
Basically there was a four-square area and you set up a sequence of where you would tap to unlock the phone. That set of squares was only shown when you set up the code
Then, to unlock your phone, you would tap those areas in the sequence you set up (even with the screen off).
Fingerprint readers are nice, but I really do miss the knock code
Edit: did find this article with a way to do the knock code, but if done wrong, could brick your phone I guess.
Plus, article is from 2014. When I looked at XDA’s info on it (they also being the developers) it looks like development on it is over, but individual modules may or may not still be supported by their devs
The batteries in them aren’t going to go past 4-5 years; I have headphones and earphones over 10 years old, with one pair about to reach the two decade mark.
That is honestly impressive. I can confidently say I’ve only owned one wired headset for a decade, and it’s the one I use for gaming so it never leaves my office.
Everything else has either broken, or been lost. Though I fully admit, serviceable wireless buds would be a thing of beauty. IIRC there are people out there actively working on the problem (other than the companies explicitly aiming for them to be a consumable forever.)