In my more unkind and direct moments I respond to the phrase "nice to meet you" by asking:
How do you now? What is your evidence for making that statement? What lets you know it is "nice" to meet me? What is "nice" about meeting me?
My curiousity is this: What would happen if we remove all automatic responses from our interactions? These are not questions anyone expects to be asked. It breaks the script. This is unkind.
Once someone responded by saying: "I take that back". And our interaction became real.