Don’t be the person who treats you the worst. Being overly self-indulgent isn’t good for you, but most people swing too hard in the other direction. No one will drive you like you’ll drive yourself, this is true – and good! But if you drove someone else as hard as you drove yourself, you’d also recognize that you had to reward that person for their efforts or the efforts would cease and they’d grow to resent you.
So don’t let that happen in your relationship with yourself. Work hard and stay diligent, but do something nice for yourself, too.