I would have to say patience. When I first started turkey hunting I was always antsy if a turkey wouldn't come in, I couldn't sit still too long, but over the years i've learned to be patient and sit still and wait them out. But the other three definately play a role too.
I agree the older I get the more patient I got and learned, that the birds when they went silent never really moved that far off. They can be called back if you have patience and that gobbler is the one you want.