Come home from work and get dressed for ballet class. Realise you still have ten minutes before it is time for you to leave. Nestle into your comfy armchair.
Realise you were wrong about the time and you have a whole hour before it is actually time to leave. Decide to get up and do something useful around the house. Just five more minutes in the comfy armchair.
Realise over an hour’s worth of five minutes has passed and you definitely should leave right now if you don’t want to be late. Walk briskly to ballet class. Arrive on time, but not early enough to warm up properly.
Have your teacher start the class with sequences of three grand pliés at the barre, instead of the usual two petit, one grand. Wave your quadriceps good-bye and proceed with your usual ballet class on legs that tremble and buckle with muscle fatigue if you bend your knees over ten degrees.
Congratulations, you have successfully wrecked your quadriceps.
During the next few days, take the time to contemplate the full extent of your stupidity whenever you find yourself taking the stairs one excruciating step at a time.