One of the GFCI outlets in our house started intermittently making a loud 60 Hz buzzing sound. I don't think it was arcing, but it was certainly getting quite warm. That's all I need to plan for an immediate replacement! (In case you were wondering, I turned off the circuit breaker.)

A little paranoia–and a sense of irony–is healthy. At our last place, a faulty smoke detector started a small electrical fire that melted much of the wire in the junction box. I wonder how many people are killed each year by mandatory safety equipment.