Many people now use ‘kind regards’ as their default sign off on emails. This sets my teeth on edge. I was brought up to describe other people (or their actions) as kind, but never to describe myself (or my own actions) as kind. Such self-praise was viewed as an unforgiveable example of ‘blowing your own trumpet’.
Inside and outside in Japan
One place where self-praise is still unthinkable is Japan. Japanese culture make a sharp distinction between the in-group (uchi: inside the house) and the out-group (soto: outside the house). The Japanese language has a complex system of honorific language to be used with members of the out-group and that must not be used with the in-group.
Blowing your own trumpet
The English expression blowing your own trumpet is odd, if you stop to think about it. It has very negative connotations. But blowing your own trumpet sounds much more hygienic than blowing anyone else’s trumpet.
So as I said in other words above, ‘kind regards’ makes me feel, well… unkind.