A man on the number 12 thanks the driver every single time, and about half the bus has picked it up from him without noticing.
That is what gratitude looks like once it stops being a feeling and becomes a way of moving through a day. Not a journal entry at bedtime — a running, low-level habit of registering that things were done for you.
Happiness tends to follow it around, not as a reward but as a side effect. It is hard to feel poorly served by the world while actively counting what it handed you.
Thank one person today who is only doing their job.