Is there a defense for speeding?

I got stopped for speeding on Thursday night. Yeah, me; the one who is a stickler for obeying the rules; the one who gets mad when someone speeds by me in a huff while I'm doing the speed limit. When I saw the cop lights on behind me and the siren demanding I pull over, my first thought was that something had malfunctioned on my car...a brake light was out or he must want to talk to me about something that only I can help him with. Something...but not speeding. Speeding didn't even cross my mind when I asked him if I was doing something wrong.

He took my license and insurance card and said he'd be back as he went to his car. I imagine, but I have no direct knowledge of this, that he was calling in my license number to see if I was a perpetual offender of the rules. Surely he'd come back to me with a warning...surely. Not a chance. He claims I was doing 50 mph in a 40.

So how do you defend yourself? What comes to mind I think are things surely to get me in more trouble.

"Sorry sir, I just wasn't paying attention."

"I was on the phone with my husband."

No, those don't sound like good defenses, even to me. I might as well tell him I was putting my make up or texting my friend. Awww....

This is going to cost me $161!

Can I go to court and just apologize? Can I explain to them that I'm really a good law abiding citizen and if they lowered the fine it would be the right thing to do?

Or do I just pay it? The officer said it won't effect my insurance since it's not over 10 mph. Aw...grrrrr....crap. My bad.