Voice calls combine the worst of real-time interactions (no chance to review what you're about to say for possible misinterpretation) with the worst of long-distance interactions (can't read body language). I literally can't for the life of me think of a worse way to interact with a human being than over the phone.
There are very few people I will call out of the blue these days but there are certainly things that are much more easily resolved with a 15 minute phone call than going back and forth on chat or email over the course of an hour.
