Gratitude is a fruit of great cultivation; you do not find it among gross people.

Gratitude is practised rather than felt spontaneously. Noticing that someone went out of their way, working out what it cost them, and saying so are three separate acts, and none of them happens automatically. People who seem naturally grateful have usually just done it often enough that the noticing has become quick. The rest of us receive a great deal and register almost none of it.

Set yourself the small discipline of naming, once a day, one thing somebody did for you that they did not have to do. Tell them where you can. The skill builds faster than you would expect, and it changes what you see.