Funny enough, my wife and I tried the envelope thing last year when our takeout spending got silly. Pulling out real cash for "fun money" each week was a total wake up call. Seeing that stack get thin by Thursday made us actually cook instead of just ordering pizza again. It felt almost silly how well it worked, like we'd found some old secret. Sticking with cash for those random buys totally changed our month end stress.
My buddy Mark got fed up with his credit card debt and switched to all cash for groceries and fun money. He said watching the actual money leave his wallet made him skip that extra coffee more times than he could count. Isn't it funny how plastic just doesn't feel real until the bill comes? He stuck with it for six months and actually saved enough for a weekend trip. Makes you wonder why we ever moved away from cash in the first place.