Wasn't too bad of a episode, it was nice to see Tyrunt's line debut here. I don't think it was that much of a sad scene, but I don't get the comments here? Bonnie's like 7 years old, it is very easy to get attached to something for a day, then be sad when it's time to say goodbye, hell it happens even when you are older, like finding a dog/cat lost and then finding out it has a owner and must go back, sure as a adult you aren't going to get all stomping about it, but even then you would be sad if you had a whole day to get to know that animal, playing with them. Bonnie didn't even have that much of a tantrum, more trying to keep her feelings inside of her.
It was sad she had to say goodbye, but she learns and grows (Again pointing out she's 7, I doubt she had to say goodbye that often to things she fell in love with).
Ash has way more experience in saying goodbye to his Pokemon (Butterfree being the first, where he had the same reaction as Bonnie, hell the way he assumed Pikachu was leaving him in that one episode). Jessie and James are also techinally adults, so they know how to handle stuff like loss, considering it's all they ever lose anyways.