I'm just the same.
I get up, and whilst doing morning constitutional things, think about really pushing it on the way into work that morning. After breakfast and washing I hit a low point, and get tempted to have any easier ride in, enjoy the views and take it easy. That last until I ride off my drive, at which point all the targets start getting at me one-by-one. Each stretch has a target maximum or target minimum. It takes a lot of effort to reach each one, but once one has been achieved, then the next one HAS to be met.
Then I get to work red hot, out of breath and sweating buckets. And I think back wistfully to the minute before I left when I thought 'I'll just take it easy today."
There is but one antidote, and it doesn't last long. That is the fast and tough ride on the weekend. If either Saturday or Sunday consisted of a Sportive pushing as fast a time as you can manage, or an Audax that pushed you further, harder and up steeper hills than you had previously imagined possible, or smashed a distance target that had been taunting you for a long time, Monday's commuting targets just doesn't seem worth the effort.
However by the next week, the effect has usually worn off.