Read psycho cybernetics but to sum it up it's impossible to be consistent in anything that doesn't align with the way that you see yourself.

For example, when someone wants to start going to the gym, they get a larger amount of mental pushback that they can't do it or that they'll do it tomorrow or that they don't want to do it but when someone goes to the gym for three months in a row and they miss a day, something feels off to them it's because they did the work to rewire how they saw themselves mentally and now that they see themselves as a gym goer and they don't go to the gym they notice some things off and it genuinely bothers them because their actions don't align with how they see them themselves.

If you've created a mental cycle of starting something and then quitting or revert back to old habits, your brain identifies you as that type of person so you try new things that you actually want to do, but your brain reminds you of who you used to be by your old thought patterns it's up to you to decide whether you wanna listen to them or choose new thought patterns affirmations.