Hi,
DH works for WJ, so I'm a little biased too
Anyway, just wanted to mention something on bringing snacks... Because you will be pre-clearing US customs, make sure that anything you bring to eat is not "fresh". ie. no fruit, no meat (like sandwiches). You would have to surrender those items when you go through US customs. You are allowed to bring anything processed (like cookies or chips).
Also, there are some places to eat once you cross through customs (like fast food etc.). That food is purchased "in the US" technically, so it is allowed to go with you. (yeah I know it doesn't make a lot of sense, but those are the rules)
As others mentioned, bring your own headset to save having to purchase a set. It is a standard walkman type headset plug in.
Even though some have mentioned that the crews tell a lot of jokes and play games, you may or may not have this happen. Some crews are good at this, and some aren't. They don't force the crews that aren't funny to try to be. Almost everyone is usually friendly and glad to help out with anything you might need.
Enjoy the flight and tell your friends. (DH is not just an employee, he's also an owner!)