My ds then 8 and I invited my best friend and her then 9 year old son on their first Disney parks trip a couple of years ago during Star Wars weekends. We had cruised together with each of our entire families a few times and had a great time each cruise so I thought they would be fine to vacation at the parks with us. My son has been going to WDW since birth and has always been more than happy at Disney. Among the things that happened over the 4 of our 5 vacation days:
First dinner was at Chef Mickeys. My friend's son didn't care to meet the characters and would not take any photos. He had literally 4 chicken nuggets and announced he was ready to leave. His mom and I started with a plate of salad and when I said I was going up for a plate of food he asked if I was really going to eat more than one plate of food. His sister called during dinner and made their mom feel guilty for not taking her too so my friend sat and cried.
Next morning we Went to Hollywood Studios and by 10:30 my friends son wanted to leave and go back and swim. I felt like we needed to show them how to get back to the resort via Disney transportation so we missed the Star Wars parade which was our favorite thing during SWW. They came back for dinner at 50s Prime Time but her son hated the waitress told "what to do." They left after dinner but we stayed for the Hyperspace Hoopla. Afterwards my son was chosen to ride Star Tours with Chewbacca and an Ewok. My friends son was mad he missed it once we told them later that night.
Day 2 we went to the Magic Kingdom and every ride was either boring, too slow, too fast, "for babies" or too scary. He told us "shorts are for wimps" and he had jeans on each day. He had one pair of jeans with him so my friend washed them each day. He got soaked on Splash Mountain and wanted to go to the resort to swim and dry his pants. He was too hot all the time in his jeans but refused to wear his shorts. They came back to MK for Wishes and we staked out a great spot an hour in advance and when the first firework started he said he had to use the bathroom so they missed it.
Next day we were going to go to AK but my friend said with her son's attitude she wasn't going to spend the money on their tickets and she wished she could fly him home early. My ds and I went to AK and had fun. My friend's son was taking photos on our Animal Kingdom Lodge balcony with her brand new camera and dropped it. It fell 5 stories and completely broke.
Last morning my friend's son woke us all up at 5:30 after he peed their bed they were sharing. He refused to be quiet in any way and we were all up for the day. We were going to go back to MK but he said "I saw the castle once, why would I want to see it again." He wanted to stay at the resort and order "free room service" and watch tv. They had been on Disney cruises with us before and he orered a lot of "free" room service and thought the Disney resorts would be the same. They stayed at the resort and swam, etc while my ds and I went to Epcot instead.
I really, really like my friend, but her son was next to impossible to deal with. I asked her if he liked the trip and she said yeah, he loved it?!?
The next year we went again during SWW with my friend and her 8 year old daughter for her daughter's first parks trip. They stayed in their own room. She was just as miserable in the parks as her brother and it got to the point I told her that everything was not always about her and what she wanted and to be nicer to her mother. She said that it was HER vacation and her mom had to do what she wanted. She also refused to wear sneakers or her new Keen sandals and would only wear her plastic dressy shoes with a heel. That didn't go over well with all the walking so she just wanted to stay at the resort and swim. My son and I did our own thing and they joined us from time to time so it ended up working out fine in the end.
I'm considering letting my DS15 take his 16 y/o best friend this June for his friend's first Disney trip, but I'm also keeping all of these stories in mind!