keep calm, get lost

Awhile ago, I made myself two motivational posters out of printer paper and a thick black sharpie and hung them with masking tape on my TV screen. One said "keep calm and carry on" and the other said "a positive attitude goes farther than a state of panic!" Can you tell which clever little slogan is world-famous and which one I came up with myself to remedy my own shortcomings? I wish I had the real, screenprinted versions from the Keep Calm Gallery; I think this series would be a nice touch hung in a row by my bedside. This postcard pack would also make an adorable gift. I especially like the shade of yellow and the typeface on "be optimistic."