I've corrected a few misconceptions from time to time.
One, that Universal Studios is not Hollywood Studios (or MGM).
Two, the number of parks and that they are NOT connected and that you cannot walk from one to another.
Three, that there are cheaper options for hotels on site. I couldn't stand to see them pay $150 a night to stay off-site in a standard hotel room because the only quote they were given was for a mod/deluxe.
I also
tried to tell an acquaintance that Christmas was the busiest time to go, but they were convinced that their own half-baked logic was sound and it would be the BEST time to go because NOONE vacations at Christmas-time. I BEGGED them to go to various websites and check first. Don't just take my word for it. Check! They didn't. Oh Well. You can't say I didn't try.
But, there are times to keep quiet.
My SIL took her three girls for one day last summer. I didn't know about it until they stopped by on their way home (we're in Indiana, she's in Oklahoma). They paid for one-day tickets to the Magic Kingdom and didn't arrive until 11 a.m.

It KILLED me to hear this.
But, the girls were just gushing about everything they did and the characters they saw. They stood in line for Tinkerbelle at noon !!!

But, they figured out fast pass fairly quickly, got a prime spot for the parade as soon as they saw the crowds forming, stayed past closing, and had a great day.
So, I kept my fat mouth shut.

No reason to ruin their great day by trying to tell them they could have done it cheaper or better.