Logging in yesterday I felt like I'd been locked out of my own house (apartment?) Google had, without prior notification (or at least I hadn't seen one), moved me over to the new user interface (boo-hiss!), leaving behind the so-called 'Legacy UI'.
I'm not opposed to... erm, progress, so I decided to give it a go, struggling for the next hour with how to...bold a piece of text! I managed, not without initial difficulty, to scramble back to safety and the Legacy UI!
A quick search soon showed I wasn't alone: the new UI seems almost universally despised/feared, see for example here.