ありがたがっちゃう
有り難がっちゃう
arigatagacchau

Godan Verb (ru)
Godan Verb (u)

The completive aspect (contracted form) - indicates completion or regret of ありがたがる

1. Thanking (excessively); Being overly grateful; (Expressing gratitude to a fault)

Completed Action
Colloquial
Usually Written in Kana