Originally Posted by
vicarious_MR'er
It's certainly not the end of the world if we can't be seated together, but someone else already touched on the reason it's nice when it DOES work out: The personal space issue. It's a lot more comfortable to share limited space with someone who is familiar as opposed to a stranger.
That being said, I've spent hundreds if not thousands of hours in planes next to strangers, so like I said, it's not the end of the world either way.
And even more so when it's an intimate partner--contact is welcome, not something to be avoided.
On the transpacific flights my wife takes the window and puts her legs over on my lap to sleep. It works quite well. She wouldn't sleep nearly as well if she had to stay within the bounds of her seat.