Gratitude vs Appreciation: what is the difference?

From my correspondence:

[7:55:31 PM] Alex Makarski: read your recent articles
i'm afraid to sound condescending
even though i know you won't take it that way
your writing keep getting better
simpler, stronger
vibrant
some time, could you explain the difference between gratitude and appreciation?
people always pile them up into the same thing and use in the same sentence
i don't know the answer but i feel you do

[8:13:30 PM] Sophie Maven: appreciation has no direction, gratitude does.
you just appreciate something, but you are grateful to someone, for something

in appreciation you don't have to acknowledge source, but you have to risk that appreciating what is will keep you stuck with it

in gratitude you need to be vulnerable to someone and take the risk of having to reciprocate, having to have earned what you got, or some other really horrible and nasty things that ego is mortally afraid of

that means, gratitude is a bigger existential risk, and therefore a higher vibration