I've never no-showed either, never even considered it. I canceled therapy sessions last minute several times, mostly when I was in a relapse with my drinking and preferred to either drink or was too sick with a hangover to go. With first T, his policy was a 24-hour notice to avoid payment and I always paid him without even a word when I gave a shorter notice. With second T, I only canceled once the night before the morning session and I was ready to pay, but he did not want me to pay and offered a session later in the week, which I took.

I never thought about skipping a session due to having ambivalent feelings about therapy or the therapist; when the negative got too much, I just stopped going altogether or took a long break (months). I do think taking breaks can be good especially if someone does feels overly hooked/preoccupied and does not like it. I had a period of similar kind of ambivalence to OPs pattern and I found it so unpleasant, I did not want to tolerate it hoping it would lead to something good. I imagine it can be quite unpredictable whether skipping when overwhelmed will make one feel better and more grounded, or perhaps still going to session would be a better remedy.

As for how it affects the therapist - I would not care about that one as long as I make my payment when we had that kind of arrangement. What I would care much more about is appearing chaotic and unable to stick to a plan, I would rather feel bad about my behavior than whatever the T might think about it. In part, because I have quite low tolerance to that sort of behavior from others as well when it becomes clear it's a pattern for them and not due to occasional unforeseen events and emergencies. A T must be prepared to tolerate and address these kinds of patterns though on an emotional level, it's not the same as acting randomly with coworkers, for example. Still, I understand that the urges and acts make you conflicted because I am sure it would be the same for me.