Unable to read data from MCP9808 using i2c
Well, add me to the long list of people who have wiring issues. I had connected the wires to the Pi on pins 1, 3, 5, and 7, but should have been using 9 instead of 7.

The important thing to observe here is that I could successfully i2cdetect the sensor and i2cdump the sensor, but not able to i2cget or i2cset the sensor.  Not sure why this is, but the facts speak for themselves.