I'd been arguing with people that said they had called me last week and left messages. I didn't have any messages. There were no message alerts, nothing to say I had even had calls from these people, no new messages when I checked voice mail. Then, this afternoon I missed a call and they left a message. Suddenly, I have messages going back to Wednesday last week. 
One of those calls from last week was time-sensitive. As a result, a pair of sheepskin boots I had bought cannot now be manufactured in time for me. I got my money back today but I had really wanted those boots.

How can messages get stuck like that? I had my phone with me, waiting for that particular call. It never rang, never came up in logs, and the message wasn't there when I checked this morning.