Too close for comfort

After a marvelous 3 day weekend, I dragged myself onto the train this morning.

I was pleased that there was one seat left.
Not pleased for long...
The guy sitting next to me decides to put his arm along the back of the seat. With every jostle of the train, his arm/hand is touching my shoulders/back.

Reasons why this is not OK.
1. Way too early in the morning for pretending this is not completely awkward.
2. Way too early in our relationship as commuters for this kind of PDA
3. How are you going to gracefully get your arm back when it gets tired? Ohh, wait, knock me in the head. Smooth operator...

It's not me, it's you...