I'm a bit outside of my area of expertise here. I'm going to try to explain the workings of the brain from a woman's perspective. Here goes:
Your hot date is due to show up in five minutes. On your last date, he transported you into realms you never knew existed, and your dopamine has been firing red hot ever since. Dopamine is the neurotransmitter associated with pleasure and reward. Dopamine neurons - that is, brain cells that fire dopamine neurotransmitters - project from the mid-brain into the limbic system, and the cortical and subcortical regions.
In other words, dopamine influences the areas of the brain involved in emotions, thinking, and modulation, respectively. This is a tad oversimplified, but let's go with it.
Your limbic system is ready to party, and the subcortical regions are resonating in harmony. Meanwhile, those brainy neurons up in the cortex are anticipating another night of splendiferous transcendent ecstasy.
What's wrong with this picture?
For one, the guy is married. He's only been clean for six weeks, he doesn't have a job, and he's in trouble with his parole officer. You know this. You need to call this off right now.
Unfortunately, the part of the brain that is supposed to be in charge - the thinking brain - is in thrall to the emotional brain. Cortex is not about to override limbic. Worse than that, cortex is rationalizing limbic. You probably know the routine:
"He's so sweet. His wife doesn't love him. He's going to take good care of me ..."
Cortex, please! Get a grip!
"... I know he has a checkered past, but I can change him. I'm going to marry him ..."
No! No! Stop it right now!
"... I want to have his baby."
And they say it's men who don't think with their brains.
Five minutes go by. Mr Right Now is not here right now. A new emotion starts to creep in. Anxiety. Limbic and cortical via subcortical are feverishly exchanging messages: "Maybe he won't show up ... No don't worry about it ... "
Another five minutes, ten. There you are pacing in your $500 Prada stilettos: He should have called by now. "Has he dumped me? Maybe I'm not good enough."
Limbic is cranking up your fight or flight response. The adrenaline is starting to pump, cortisol is entering the blood stream. Your dopamine is still popping, but it's starting to drive a new emotion, anger.
"Damnit! Why hasn't he called!"
Ten, fifteen minutes go by. You're not about to greet lover boy with a wet kiss. There's still the prospect of make-up sex ...
Another fifteen minutes. No jury would ever convict you.
An hour goes by. You're spent, emotionally drained. You're slumped on the sofa, Prada shoes on the floor where the dog can chew them. The adrenaline has receded, your dopamine has depleted, along with other key neurotransmitters. Cortisol is still kicking around in the system. You are in a state of despair, utter hopelessness, self-esteem at an all-time low. You are depressed.