I once attended a Training Course where the Conditions White, Green, Yellow, and Red of Pilot Attentiveness was discussed.
It made a lot of sense back then and bears repeating.
White.....you are somewhere warm, cozy, smelling of fine perfume and freshly washed Hair....or whatever equivalence does that for you. Things are safe, your mind is anywhere but in the Cockpit.
Green....you are in the Cockpit, everything is going fine, the weather is great, bags of fuel, things are just going as planned.
Yellow....You are in the Cockpit and sitting a bit more upright than normal...something is not quite right but nothing dire noticed yet.
Red....You are sat straight up....you Heart is over speeding....you stomach is in your throat...butt cheeks clinched tight enough you could trade the Shoulder Harness and Lap Belt for a Trailer Hitch Ball and be firmly fixed to the seat....and lots of stuff is going badly wrong.
Transition from each Condition/Mode should be gradual, unhurried, and planned ahead....the rate of change causes distress the quicker it happens....with a significantly reduced accuracy in reaction time and appropriateness of that reaction.
We should never go more than one Condition per change....and never knowingly operate in either White or Red Modes.
Green is fine....but Yellow is the best.
That means you are awake, thinking, checking what needs to be checked, monitoring what needs monitoring, and making sure your plans are still intact and if not you are aware of it and taking corrective action.
If some thing goes wrong....it will not be a surprise or shock to you...even if you only generate a mere second or two of advance warning.
Get yourself a Yellow Sticker and put it somewhere you will see it in your Cockpit....it works!