You must answer the phone. If you do not answer the phone, your boss will notice. He will not say anything, but he will disapprove, and you will feel his disapproval deep down inside. If you do not answer the phone people will leave passive aggressive messages. Later they will tell you "I called, but no one answered." I was at lunch, you will think. I was dealing with the homeless man who wanted to apologize for being rude, but spoke in such an aggressive way that I just wanted it to end. He mentioned his medication. It was a genuine apology; he was trying so hard, poor crazy bastard. Of course, you will not say that to this person whose phone call you missed. "I'm sorry about that," you will say. Your apology is not genuine.
You have been answering phones for your entire "professional" life. First as the receptionist at a church, then as the administrative assistant/office manager at a small non-profit, now as the parish administrator at another Episcopal church. You used to have to work yourself up to it. You'd wait until the third ring, just before the answering machine kicked in, building up the courage to speak to another stranger, to open that black box, to take that little leap and find out what this new voice will demand of you: a salesman trying to sell you a new copier, an angry parishioner who wants to discuss the service leaflet, a reporter, an inmate from the local prison.
Slowly, you grew accustomed to the phone, the black receiver against your ear, pressing hold, transferring calls. You memorized the names and voices of the regular callers, and began to enjoy hanging up on salesmen. You learned to speak about half an octave above your normal register so you sound friendly, to be vague about whether your boss is in, to never promise anything. Now you pick it up on the first ring. Almost always.