>finally beat the game today
>after a long and difficult battle to become champion of alola due to having a team of only four pokemon who barely met the "requirements" to be at the elite four
>everyone is happy and celebrating afterward but there's a bit of a melancholy feeling coming from lillie
>the next day lillie leaves forever (within the game at least, as I haven't heard of her coming back at all, the opposite actually)

Isn't the player supposed to feel excited and happy to beat the elite four and become champion?

I never felt sad in the older games when I got to this point. I felt great. Yet now I'm depressed and feeling like I should just reset the game so it doesn't save and then never progress again so I don't have to make things sad and lose Lillie forever.

Guys this is too sad why did they make this sad. Lillie and my female trainer were supposed to be together forever... I got really attached to her... She's too cute and you could tell she had feelings for the protagonist. ; n ;