The person on the other end doesn't know if you are making yourself deliberately hard to contact, or if you are genuinely unable to answer the phone call. This

The person on the other end doesn't know if you are making yourself deliberately hard to contact, or if you are genuinely unable to answer the phone call. This strategy works fine in my experience. Most important calls I get are from people already in my address book. If I'm in a job hunting phase, I'll answer calls from numbers I don't recognize during time frames when I am expecting them (e.g. the policy is relaxed for the duration of a job hunt). But, outside of that, it's hard to imagine a call from someone I don't know that is so important I can't let it go to voicemail, but so unimportant that the caller will deign not to leave a voicemail to let me know this is really important.