A senior colleague will often instant message me in a way i think is slightly rude / cold.
For example, she will write in an IM, 'I need this by 11:30' or 'How much is xxx'.
I normal would start my messages with a Hello or Hi or some form of greeting.
i've started to communicate with her in exactly the same way; no greetings or hello, but i was asked by my manager to be more polite, after she was copied in on a few emails.