After nearly cutting off my finger in a bandsaw at work, I have A LOT more respect for power tools than I once had. I will use the table saw or circular saw alone, but I always think about exactly what I'm doing before I do it and think, "Now how could this go wrong?" It probably would be safer if someone was around but at least I am aware of the danger.
At work, there are way too many things that would kill me quick and nobody would find me til the next morning. I don't risk it if I'm there late. My job isn't that important!
And I always make sure my cell phone is in my pocket, in case I need to get to it with my non-bloody stump.