This is why I'm slowly going crazy

In my house, one conversation occurs on an almost nightly basis:

Me: "Mark, get in the shower."

Mark (incredulous): "WHAT? I just took one THREE DAYS AGO!!"

Me: "Exactly."

After five minutes of complaining, three minutes of stomping around his room, and one minute of slamming, then re-slamming the bathroom door (to make sure I heard it), Mark gets into the shower.

Where he stays for at least 30 minutes, until I pound on the door.

And then he screams, "WHAT??? Come on, I just got in!!!"

And I sigh, and pound my head on the wall.

The back-and-forth doesn't irritate me as much any more, mostly because I go on autopilot immediately after telling Mark to shower. Most of the time, I don't even remember the ensuing negotiation.

But last night...last night was the night that reminded me Mark's real purpose in life is to drive me insane.

Mark went into the bathroom, and eventually started the shower. It was running for a good five minutes when I walked down the hall, and suddenly heard the sink faucet go on. (Who's turning on the faucet if Mark's in the shower??)

I frowned, opened the door, and there was Mark, wrapped in a towel, head down in the sink, hair sopping wet, with the shower running full blast directly behind him. 

I immediately knew what he was up to--faking a shower. (He was dumb enough to tell me he does this at camp to fool his counselors--and I was dumb enough not to check him every time after he told me that.)

Mark then did what he always does when I catch him misbehaving--he freaked.

"SHUT THE DOOR!" he screamed, tugging tightly on his towel, as if I'd intruded on his modesty, instead of his ethics. "What are you doing???" He slammed the door, then clicked the lock.

I just stood there, stunned. I wondered how many years this has been going on for, and how many times I've been duped into thinking Mark's showered, when really, he's just hanging out, reading his books and relaxing. And running up my water bill.

I walked to the guest room, where my sister-in-law Mari was sitting. With barely contained laughter, I relayed what I'd just witnessed, including the panicked look on Mark's face when I opened the door.

"That is Mark in a nutshell," I said. "He'll spend 30 minutes faking a shower, and 15 minutes pretending to dry off, instead of just getting in the stinking shower for five minutes!"

We laughed our heads off, stopping only when Mark turned the shower off and could hear us. Even then, we reverted to silent giggles.

Seriously...anyone want a half-clean (but full attitude) 13-year-old?