I think somewhere along the line, software developers have stopped learning about the principle of blocking / non-blocking operations and "not blocking the UI thread". Or, at least, enough people who don't know about this principle are submitting code that ends up in OSes and applications that we are now all suffering for it.

It really feels like the types of software which have inexplicable pauses / hiccups has grown. Sometimes even my OS (a Debian flavor, although it's a corporate managed distribution that might be to blame) locks up from time to time when I'm tethering on my phone with limited bandwidth, which is highly suspicious.