Old houses have one tap that never quite runs hot. The boiler is fine. Something in between is narrow, or airlocked, or was plumbed in badly forty years ago by a man in a hurry.
Kindness towards yourself often runs the same way — plentiful in one room, absent from another. People who are patient about their own mistakes at work can be brutal about their own body, or the exact reverse.
The heart can be warm while the mind is still running an audit. Notice which tap is cold. That's plumbing, not character.