Identity change is necessary for long-term behavior change
"I'm trying to stop drinking" vs. "I don't drink"
"I'm trying to quit" says this is something you want to do but is not yet reconciled with your identity. When your willpower is tested you'll have to choose which identity will prevail: the one who used to drink or the one who is trying not to.
"I don't drink" says this is who I am. There is no confusion. It's not a matter of willpower, simply a matter of The-Way-You-Are. Even if you feel the desire to drink, you have established this habit as part of your identity, and so now you're a person who doesn't drink.
Changing identity directly is not only powerful internally but also externally. You'll be more likely to tell others about your commitment. You'll have social pressure to be consistent. It's embarrassing to fail to be the person you told everyone else you were.
It is useful to use systems and successive small wins to prove an identity change to yourself (Systems are better than goals).
"Every action is a vote for the type of person you want to become"
TLDR:
When a habit or behavior becomes ingrained in your identity, it is unlikely to change. Identity is what we do repeatedly. You can take advantage of this fact by starting to change your identity as a means of changing behavior.
References:
Atomic Habits "Every action is a vote for the type of person you want to become"
"The ultimate form of intrinsic motivation is when a habit becomes part of your identity. It's one thing to say I'm the type of person who wants this. It's something very different to say I'm the type of person who is this."
"Once your pride gets involved, you'll fight tooth and nail to maintain your habits"
"Ultimately, your habits matter because they help you become the type of person you wish to be. They are the channel through which you develop your deepest beliefs about yourself. Quite literally, you become your habits"
The Almanack of Naval Ravikant
For self-improvement without self-discipline, update your self-image.
When you wake up in the morning and head to the gym, the benefit of that choice isn’t just in the calories you burn or the muscle tone you develop that day. The benefit also lies in the fact that you’re reinforcing valuable skills and habits.