It doesn’t matter if you feel great. It matters that you have a routine.
You can do all the right things — eat well, sleep well, and train well — and on the day of competition you wake up and you don’t feel great. But it’s still just a feeling, a feeling you might be able to live with for a while.
Routines diminish the need to feel great.
This point gets hammered into track and field athletes all the time, and it gets hammered into swimmers and divers all the time. They don’t get the luxury of hiding behind teammates if they’re having a bad day. Their scores are there for everyone to see, with nobody else to blame.
So they do the same routine, day after day, the same way every time. It becomes a buffer against feelings.
You have to write your thesis, your capstone, do applications for graduate school, or study for your final exam. If you’re feeling great that day you’ll get them done.
If you have a routine, you’ll get them done regardless.