I don't think I'm being unreasonable but it's happening so much that I'm wondering if I am!
For example, you introduce yourself to someone as "Katherine" and they reply with "hello Katie". It gets my back up. When I've politely corrected them and said "It's Katherine" they appear to get irked that you've corrected them.
Katherine isn't my name but it's a similarly long name and I just don't like the shortened versions so prefer my given name.
AIBU?