That ending made no sense

That is why it made sense for Woody to stay with Bo.

"Well the reason why he left is because Bonnie didn’t care about him and that was my biggest problem with the movie. Andy specifically told Bonnie that Woody was special and to take extra care of him. Which she didn’t at all. I honestly hope we get a 5th one where the gang gets back together and all become “lost” toys because Bonnie is going to grow up and forgot about them."

Honestly, I'm not sure how Bonnie would react to Woody not being there.

On the one hand, we see her crying her guts out for I think two straight days when she realizes Forky is missing - but never seems to notice that Woody went missing too.

On the other, you're right in that Andy specifically entrusted Woody to Bonnie's care. She knows he's a special toy.

Now, to be fair to Bonnie, SHE didn't throw Woody aside - he bailed on HER. Yes, she put him in the closet, but Andy put ALL his toys in the toy chest and forgot about them - it didn't mean he abandoned them, just that he didn't want to play with them anymore. Bonnie didn't throw Woody in the trash, she just set him aside. There's a difference.

So it's very possible that when Bonnie realizes Woody IS gone (which she hasn't even done at the end of the movie), she'll be mortified and cry as hard as she did over Forky. What struck me as VERY odd, and totally outside of Woody's character, is that he never once considers Bonnie's reaction to him going missing, or seems to consider her at all - his decision to stay behind is 100% selfish.

Yeah, Buzz says "Bonnie will be fine" with Woody, but how the heck does HE know? And what does that mean, anyway? Is Buzz saying "Yeah, Bonnie doesn't care about you, she's got so many toys she'll never even notice you missing!"? Or to go even deeper, "Bonnie is turning out to be one feckless, fickle little jerk. She isn't Andy, who deeply loved his toys - she's superficial, a little Paris Hilton. You deserve better, she's so shallow she can't appreciate you!"

I would have accepted that premise IF Woody had at some point stated that he was looking for new purpose and wasn't interested in being a kid's toy anymore.

But he never said that; in fact, his whole character over 4 movies was all about how important it was to be loved by a kid and to be a kid's toy. He was specifically entrusted to Bonnie by Andy; he should have held that sacred. It would have been MUCH more in Woody's character for him to say "Bonnie isn't playing with me right now, but it doesn't matter. She was chosen by Andy to be my new owner and I'll be there for her until Bonnie gives me away herself."

Wanderlust has never EVER been a part of Woody's character, but at the end of TS4 he chucks everything to stay with Bo - who, we are shown,doesn't share his values at all. It's a weird choice for him to make. And he completely disregards Bonnie's wishes, something that's completely out of character for him. So what if Bonnie put him in the closet? Andy put him in the toy box for a decade, it didn't make any difference. Bonnie didn't love Woody the way Andy did, but that doesn't mean she won't be sad when she realizes he's missing.

Woody reneged on his unspoken oath to always be there for his owner. That's an astonishing heel turn for him. Astonishing, and really bad storytelling.

OK, but Andy abandoned Woody in a toy chest for what, nine years? Woody didn't have a crisis then. Toy Story 3 was all about Woody trying to get all the toys BACK to Andy despite the fact all the toys claimed Andy had forgotten them.

ALL of the movies have followed the same pattern: Toy fears abandonment, Woody bolsters/helps them, and toy either finds a new owner or goes back to their old owner.

Toy Story: Woody fights Buzz for a place as Andy's favorite toy

Toy Story 2: Woody consoles Wheezy, who fears abandonment. Woody becomes a 'lost toy' and spends the movie helping Jessie, who was abandoned and is traumatized by it.

Toy Story 3: Woody has to get the rest of the toys back to Andy's when they are accidentally given to a day care center.

That's Woody's entire raison d'etre, helping toys connect with owners. It's his mission. He's the sentinel, making sure that everything is right in his "town".

He's never developed wanderlust. He's never said "You know what? Maybe it's time to move on. I don't need to be a kid's toy. I'll be fine on my own."

Even in TS4, when Bo talks about how great it is to be on her own, he argues with her. He very clearly does NOT believe the way she does. There's nothing in the movie that even hints that he doesn't want to be Bonnie's toy anymore.

Until the end, when he bails on her. It's not Bonnie's decision; Woody doesn't give her the choice to let him go, he just leaves. This after spending the entire movie ARGUING with Bo about how important it is to belong to a kid. This after giving up his voice box so Gabby can get a kid.

If Woody had at any point in the movie said "You know, this is great. I feel great doing this! Better than I have in a long time. Maybe this can be my new purpose in life" I could have bought the ending.

But he never says that, and he never acts like abandoning Bonnie has entered his mind. Until two minutes before the end of the movie, when he does it. It's sloppy storytelling.

Wouldn't it have been neat if an adult Sid with his child was at the carnival trying to win toys for his son who only planned to mangle them - or blow them up? Woody and his crew weren't "matching up" kids and toys - they were passing out the toys at random.

Not having a 1950s voice box/pull string would have meant ZERO to any modern-day child, not in this day of computer-chip driven vocals. To a collector, of course, yes, but the fact that Woody was cut open to remove his voice box destroyed his value to a collector anyway. Even if he got his voice box back, or got another one, he's got a huge vertical cut in his costume.