I don't disagree about the common courtesy part, but I don't know what you mean about "silly to act like money doesn't matter" as I've been saying all along it does matter.
OP mentioned that this time they bought "ton of stuff". It's possible their friend felt it was too much. Sure, they should have thanked but if they felt overwhelmed and pressured to give as much or more, maybe silence was all they could think of.
I don't blame OP's feelings. I would have been hurt in the same situation, but notice the tone OP is already talking about their friend: "knowing that not only will the favor not be returned, but they'll LIE about it".
The trust is gone if after one incident (that they have never even discussed), OP knows they are never going to get any gifts from their friend anymore, and they know the friend will lie to them in the future.
ayrt
OP mentioned that this time they bought "ton of stuff". It's possible their friend felt it was too much. Sure, they should have thanked but if they felt overwhelmed and pressured to give as much or more, maybe silence was all they could think of.
I don't blame OP's feelings. I would have been hurt in the same situation, but notice the tone OP is already talking about their friend: "knowing that not only will the favor not be returned, but they'll LIE about it".
The trust is gone if after one incident (that they have never even discussed), OP knows they are never going to get any gifts from their friend anymore, and they know the friend will lie to them in the future.