Its happened to me as well awhile ago. Took 2 attempts. Was 6pm and not freezing out or anything.
A couple times it will start but the rpms are super low and it sounds like it wants to go back into slumber. Then all of a sudden it will shoot to 2000rpm without me touching anything. I think this has only happened on cold mornings, 6am.
I just caress the steering wheel and say "i know baby, i know..."