"Thought for the day"
We used to have these back in school. Sometimes, I'd choose to take it literally, to let it be the sole thing that occupied my mindspace all day. I'd often be tempted to actually learn stuff that day, or to, yknow, talk to folks, but I'm sure wiser minds than mine had deemed the 'thought for the day' truly encompassing enough to sustain.
So, on the day, my credo could be: 'It is terrible to speak well and be wrong.' - Sophocles or 'Not failure, but low aim, is crime.' -J.R. Lowell
or some other such. And call it a genetic virasat, but I could always blank my slate save the thought for the day. Got into much trouble.