Nature is a mutable cloud which is always and never the same.

Everything around you is in continuous change while keeping a recognisable shape, which is why it looks stable from a distance and never repeats up close. A river, a city, a marriage, a body: each is the same thing and a different thing depending on the timescale you use. Expecting permanence from any of them is a small category error that produces a lot of unnecessary surprise.

Take something you assume is fixed and ask when you last actually looked at it. A relationship, a job, an opinion about somebody. Check the current version rather than the one you filed away, and adjust to what is there now.