I identified with this for my running and my taekwondo. The trick with taekwondo is simple: always go. If that’s the default position, it’s easier. These are the steps I take: always take my kit to work, regardless of how rough I feel in the morning. Always at least walk to the venue, even if I don’t think I want to train. Once I’m there, just go in the door.
Exceptions to this are when I’m ill enough to not go to work, or for big events such as long-lost friends coming to town, family birthdays etc. Balance is important as well.
And I wish I could get the same rhythm with developing my running. That one’s tough for me.