Physio exercises are boring, slightly humiliating, and don't work for about three weeks. Anyone who quits does so in week two, on entirely reasonable grounds: there is no evidence yet.
Self-compassion has a similar curve. Spoken to yourself kindly on a bad Monday it lands as false — the ear rejects it, having been trained on something harsher for thirty years. That rejection isn't proof it is wrong. It is what any unfamiliar input sounds like at the start. What changes first isn't the belief, it is how long the harsh version gets to run before something interrupts it.