Understanding Engineers

Did I already post this one? Worth repeating if I did...

An engineer was crossing a road one day when a frog called out to him
and said: "If you kiss me I'll turn into a beautiful princess".
He bent over, picked up the frog and put it in his pocket. The frog
spoke up again and said: "If you kiss me and turn me back into a
beautiful princess, I'll stay
with you."
The engineer took the frog out of his pocket, smiled at it and returned
it to the pocket. The frog then cried out: "If you kiss me and turn
me back into a princess, I'll stay with you and do ANYTHING you want."
Again the engineer took the frog out, smiled at it and put it back into
his pocket. Finally the frog asked: "What is the matter? I've told
you I'm a beautiful princess, that I'll stay with you and do
anything you want. Why won't you kiss me?"
The engineer said:
"Look I'm an engineer. I don't have time for a girlfriend, but a
talking frog, now that's cool."