I remember going to WDW when I was in 1st grade. My parents had a huge motor home and they were taking my grandparents and my uncle (who was a bit younger than my brother!) So my parents wanted me to have a friend, so I invited a friend from my class. We drove to FL, seeing sights along the way, spent a few days at WDW, then drove back.
What this friend's parents failed to mention was that Diane (my friend) wet the bed....every night! So every day we had to pull the motor home into a laundry mat and my mom had to wash the sheets.

Then at the first place we went, my mom says to Diane, "Would you like to pick out a small souvenier from here?" Diane pulls out her "souvenier money" and it's a whopping $5!!! Mom sent her with $5 and nothing else!!
Let's just say between my dad having to spend so much time with his in-laws, my grandma refusing to help at all with meals or clean up or anything, my brother and my uncle fighting ALL the time, and the Diane issues, it wasn't that much fun.
Now, 5 yrs ago we took dh's younger sister (she was 13 at the time) on a 2 week trip. Night number 1, she was crying in the Artist Point bathroom b/c she was miserably homesick. She spent an hour on the phone every night crying to her mom. She couldn't wait to get home. We paid all expenses.
4 yrs ago we took my neice on a WDW cruise and 9 days at Disney....she was 18. She spent LOTS of time on the cell phone to her friends back home. Skulked around and hardly smiled. Found every excuse to go back to the room to sleep and/or talk on her phone. We paid all expenses.
You'd think we'd learn. Of course, Dh's sister and my neice all talk about what a WONDERFUL time they had at WDW. Would have been nice if they'd have shown it THEN.
Dd wants to take a friend sometime, but I don't think I'll ever go there! Our trips are usually 2 weeks and that's a LOOONNNGGG time to have to deal with someone else's kid! Her one friend was homesick and crying when dd took her to her youth group meeting a couple years ago....30 minutes away. No WAY I'm taking that girl to WDW 1000 miles away!!!!