WIY I completely disagree. COMPLETELY! What you say :
“If the lack of a thank you bothers you, then your Chesed is lacking in Lishma that’s the vort. Chesed is a Mitzvah that Hashem commanded us to do, doing Chesed is emulating Hashems ways..”
Acually I believe that if a person takes and takes and is such that they are a Take-everything-for-granted-type-of-TAKER THEN YOU ARE ACTUALLY m’chiev to stop giving! You are doing them a disservice by putting in front of them a stumbling block. They are not grateful and therefore have a major spiritual/midda deficeit. WHy feed it?
True, its your problem that you are bothered. But who wouldnt be?