What is the difference between you are too kind and you are very kind?
too kind MacMillan Dictionary
used for thanking someone in a way that is very polite but not
And from You're Too Kind -
A Brief History of Flattery
By RICHARD STENGEL, we can again find some negative connotation. Depending on the context, of course. The article is a fascinating read and somewhat a narrative etymology of self love and flattery.
That ironic tone is so often the cloak for all flattery, indeed all
praise, these days. What we think of as flattery is usually delivered
with an air of arch knowingness, a kind of self-consciousness that
says, We all know this is flattery, so don't consider me a weaselly
little brownnose for saying it. In fact, these days we struggle to
invent new ways to praise people because the traditional methods are
seen as a worn-out currency.
This leaves the other compliments such as kind and very kind to their literal meanings, stripped bare of most other connotations. Of course, context is critical in perceiving the meaning of 'too kind' and 'very kind'.