I have "seen" it happen or I have perceived it happening to me often enough. I can't explain all the inner workings, but some feelings cause a physical reaction: a twinge of the gut or that feeling in your toe (?)

Just to take gut twinging as an example. I have, in chronological order

1. I receive input (visual....browsing youtube thumbnails)
2. I feel a twinge in my gut
3. My eyeballs retrace their route back to the stimulus (a particular thumbnail)
4. (something mysterious happens)
5. I recall realize the connection between the content of the thumbnail and the dumb thing I said years ago

Now, I hope that's relatable because of course it's mildly embarrassing, as a human, to make an ordered list of the steps of your feels. But...feels is a universal and fundamental part of being human, so let's go there.

Emotions are a part of how your brain works. They are a tag that gets associated with a "thought" (recalled memory, stimulus that relates to information that you at some level regard as "important"; feel free to supply your own definition.)

There is a "thing", we will call it a thought because (we think) it involves brain chemistry happening inside your skull. If we call an emotion a "tag" or if we say emotion A is coupled to thought(s) Z I think we can agree that emotions are come along with a thoughts.

Chronology can just be my perception, mind. We're supposed to be about a quarter second behind "objective reality". If only two of the above steps are less than a quarter second apart (very likely; it all probably happened in under a full second), a "last minute" process somewhere could easily swap the two and present the ordering to my consciousness in a way that contradicts reality.

Is any of this testable? I mean, don't plan on me being an easy subject to study. Put a bunch of wires on and walk around all day waiting to have an "emotion"; how about rage?

Think of the power that your learning machine (mind) has to emphasize certain things (walked into the wrong bathroom in 6th grade) if it can trick you by first making you "feel" bad about your self and then, 'right after that' letting your mind stew in the whatever your senses are picking up that you now feel bad about.

If you weren't paying attention you might have the following "happen" to you

1. Suddenly I feel like a super shitty person
2. And oh, unrelated and as if to emphasize this, here on the new elementary school blueprints I'm looking at, is a box marked "Girls Bathroom" and that only further^* emphasizes the point ;-(

Or, if you more swing sociopath

1. I feel like a thoroughly superior human being all the sudden
2. Hah, and look, a News show about how dumb people in that particular country are!

It's a curve-bender that has destructive power either way.

It's time you stand up and demand your mind show you that sausage factory! It's there, it's core to your being (you live entirely on mind sausage), so you are going to want to take a tour.