If you only kept promises when you want to, they wouldn’t be promises. Does your current self really think that feeling lazy is a good reason to break the promise? I kinda expect toy-you would feel bad about breaking this promise, which, even if they do it, suggests they didn’t think it was a good idea.
If the gym was currently on fire, you’d probably feel more justified breaking the promise. But the promise is still broken. What’s the difference in those two breaks, except that current you thinks “the gym is on fire” is a good reason, and “I’m feeling lazy” is a bad reason? You could think about this as “what would your past self say if you gave this excuse?” Which could be useful, but can only be judged based on what your current self thinks.
If you only kept promises when you want to, they wouldn’t be promises. Does your current self really think that feeling lazy is a good reason to break the promise? I kinda expect toy-you would feel bad about breaking this promise, which, even if they do it, suggests they didn’t think it was a good idea.
If the gym was currently on fire, you’d probably feel more justified breaking the promise. But the promise is still broken. What’s the difference in those two breaks, except that current you thinks “the gym is on fire” is a good reason, and “I’m feeling lazy” is a bad reason? You could think about this as “what would your past self say if you gave this excuse?” Which could be useful, but can only be judged based on what your current self thinks.