I want my feelings punched out as well.
If there's one thing I like better about cartoons today than ones from the 80's and 90's, it's the willingness to have a series end with an ending instead of perma-reruns and no closure. Especially the 1980's "trapped in a magical dimension" cartoons like Captain N. Never got out of there.
But what closure! This finale was a nice character arc for Mabel, as well as Dipper and Stan. I'd say it's one of those times you knew the jerkiest character would redeem himself, but it was done with a nice "will he or won't he" moment that plays out satisfying enough not to matter. You know it was the last episode because they played the theme song during a fight sequence in a show that never plays an underscore of its own theme. Great to see a lot of one shot characters pop back up, even if just for a short moment.
On that note, the one thing I was pretty happy about was during the epilogue, Soos and his girlfriend are working at the Mystery Shack. The one thing that I kinda wanted to see was closure with those two, since she wasn't in any of the action sequences or even at the birthday party. Soos really deserved to have her. Also, because i didn't comment on part 2, I felt the part where he imagined his ideal father sad in a sweet sort of way. That's one of the threads they left frustraitingly open, though. Not giving Soos real closure with his real dad, even though he stopped caring about it at the end of "Blendin's Game."
Still, I hope there's some possibility for a TV special or film length episode in the future. Seems there could be some potential left for the Twins coming back next summer, or at least Stanford and Stanley's around the world journey.