Some days you just don't have 100% to give. (Perhaps that perfectly describes you this Monday morning?) When you are too worn down to give it your all, give it your half. Or give it your 20%.
Doing something is better than doing nothing at all.
I'm applying this to my workouts this week. Recently, I've been pretty sedentary. My excuses include working on other projects, the weather and watching our dog. (Hahaha! Even the dog is getting the blame.)
Part of my mindset says, "If I don't have time for an hour workout, I might as well not workout at all." (Insert eyeroll at yet another excuse.)
Doing something - like taking the dog for a longer walk or doing yoga for 10 minutes in the morning - those are all very possible. Or like this morning, I walked up the six flights of steps to work instead of taking the elevator. It's better than nothing.
When you can't give it your all, just do what you can.