kill with kindness
Overwhelm or harm someone with mistaken or excessive benevolence. For example, Aunt Mary constantly sends Jane chocolates and cake and other goodies, even though she's been told Jane's on a dietnothing like killing with kindness. This expression originated as kill with kindness as fond apes do their young (presumably crushing them to death in a hug) and was a proverb by the mid-1500s.
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.