Mobile Etiquette

I have recently stopped answering my mobile and told people they have to email me to get in touch. I am writing up a 20 k word dissertation and I don't want to be disturbed. During the limited leisure time I have, I wish to be disturbed even less. I find phones, especially mobiles are very intrusive. If somebody calls, they are assuming that if I am not otherwise engaged, I am willing to speak to them immediately, then and there.

I have a landline and only one person (my partner) has the number as he is the only person who I never mind being interupted by! In hindsight, keeping this number private has been a very good decision!

The look on people's faces when I tell them that I am no longer contactable by phone is one of horror... why can't they accept my choice or am I really being unreasonable?