Something about the major plotpoint of the Muppet 15 demanding there be fifteen of everything for the party reminds me of the old animated insert of Princess Twelvia.
The obnoxiousness of the character's hissy fits over not getting their way are reminiscent of younger children or "brats". Perhaps the problem is that we're expecting to be entertained/made to laugh with the funness of how we view Sesame nowadays versus what they used to do in teach life-lessons so that you'd recognize it's a life-lesson. That's pretty much in line with their self-regulation core concept for the season.
The funny thing is hat if you look at the Numericon episode and then this, it pairs poorly. In Numericon, when something happened that disappointed everyone else, Elmo came to the rescue. And then when something went wrong for him, Leela sat down and give him a pep talk...err...pep song, and it was quite a good message for their self regulation curriculum. This episode played 15's crying as a joke, and the lesson was about counting to fifteen with a small helping of Hispanic culture thrown in. While I get the concept is it's supposed to make fun of spoiled girls who get these right of passage birthdays and want everything to be perfect to a controlling way, the execution was just bad.
Essentially the episode was like this.
"WAAAAAH! I'm the number 15 and I deserve a celebration about the number 15!"
"WHAT?!? You threw this thing on the spot to stop me from having a temper tantrum and
you don't have [such and such]?!?! WAAAAAAHHHH!!!"
"WHAT?!?! You actually managed to scramble to find these things but there's not 15 of them?!?! WAAAAAAAAH!!!"
(repeat lines 2 and 3 over and over at least 4 times).
Now, if they played it that the 15 felt left out and was kinda depressed about things, it would have worked. If they called out and told her to calm down, it would have worked. But they basically just kept giving in to
insane illogical degrees. At one point, after throwing a fit that they didn't have any food (Sesame Street be darned, food needs to be prepared or bought), they scrambled up 2 plates of food of fifteen pieces each (tamales and empinadas), she
threw a fit because combined that makes thirty pieces of food. Now, yeah... for the sake of the math concepts they had to teach division and what 2 numbers add up to 15. But if there was 15 people at the party, that's only one piece of food per person. What is this? The WESAYSO company picnic? But the illogic continued with 15
demanding 15 dancers. not 15 party guests. 15 people dancing for her entertainment. So, the guest list is over 15 at this point, so there's not even enough food to go around.
Just... this episode rubbed me the wrong way. I really wanted Telly and Mando to march up and say "we're throwing this thing to be nice because we felt sorry for your first outburst. We're
trying. This isn't your birthday, just your amount." Comedic effect or nothing, 15 was never called out on anything.