In the book "Thou Shall Prosper," Rabbi Daniel Lapin talks about forming friendships by creating ongoing obligations.
He says in Judaism, that 'friend' means indebtedness. Accepting gifts creates vulnerability; we are saying that the gift was something that we are better off with. You're admitting that you had a need when you say thank you. You're putting yourself in debt to them for receiving that gift. It puts you in a mind of wanting to repay it with a similar good deed. Creating this regularly sustains and nurtures a good friendship.
Learning how to accept a gift is a skill to be learned. I've seen this many times in my own life where a compliment gets deflected, and I can unconsciously hear the receiver insulting the one giving the compliment by saying they don't know what they're talking about.
Receiving a gift or service must be done with open arms, not shying away from what is given. When you fully receive a gift, you give honor to the one giving it and show that you are indebted to them. Saying that you are better off for what they did for you.
Key takeaways:
1) Friendship & 'thank you' means indebtedness
2) Good friendships are built on a constant cycle of obligations
3) Learn how to receive a gift openly, not downplaying it