"The harder I worked, the luckier I got". I don't know if he said it first but Ralph Engelstad used it. He was the man who donated close to 100 million dollars to build a new hockey arena for the University of North Dakota.
"Faith makes things possible... not easy". My wife has that on our kitchen wall.
And finally,(although maybe not appropriate for your man cave) I posted this on my computer in my office at work a few years before I retired, just to remind me: "This is not my home, I am just passing through."