Because Jesus is God - when Jesus says something, God is saying something. When Jesus does something, God is doing something. And when Jesus feels something, we're given a picture into how God feels about something. And DESPITE being God, Jesus spent a ridiculous amount of time around ORDINARY people - people who weren't necessarily the brightest, most beautiful, or most powerful. And we see something VERY IMPORTANT in the call Jesus issues to Peter, James, John, and Matthew.