I wish I’d listened to Mr Waits when he said “Never trust a man in a blue trench coat”. I didn’t and got shafted.
“noli illegitemi te carborundum” is always good advice as is “aut dure aut domum'”* which was mentioned upthread.
* a motto’s no good if it’s not in an obscure, dead language. Which reminds of another good one: “latin’s an ancient language, as dead as dead can be. It killed the ancient Romans and now it’s killing me”
But my mantra is “It’s only impossible if you stop and think about it”