What is one hidden setting most people do not know exists that genuinely improved your device

[WearyScholar]

Modern devices are absolutely packed with settings buried several menus deep that most users never encounter unless they specifically go looking for them or stumble across a tip online, and some of these hidden options can genuinely transform how a device feels to actually use day to day, from battery saving tweaks that quietly extend a phone's life, to accessibility features that turn out to be genuinely useful for people without any specific accessibility need at all, to developer options that unlock functionality most users never realise their device actually has.

These settings rarely get any real attention from manufacturers themselves, buried away as they usually are, which means most people only ever discover them through word of mouth, a specific forum post, or pure accident while poking around a settings menu out of boredom. What is the one hidden setting or feature you discovered that genuinely made a noticeable difference to how you use your own device?

[Merchant97]

Enabling developer options on Android to reduce animation speeds made my entire phone feel noticeably snappier, and barely anyone seems to know that setting even exists.