Drivers. What circumstances would you give a one-star rating to your passenger?

Actually having done a couple thousand rides, I don't think I've ever given a 1-star.  I had one trip were I would have, but the ride requesting customer was not in my car - rather he had ordered the ride for a couple of employee's that were complete idiots and furthermore puked in the car.  So i didn't... but in hindsight, I should have!

 if somebody has to be rated two or one star that means that there's a problem and I would end that problem before they reach their destination by canceling the ride

1 star ratings are really really rare. You have to do something to completely piss me off. I think I have only ever given a 1 star 2-3 times and all times were because the passenger was being a complete jerk, drunk, yelling at me, treating my car poorly, etc.

You ask for "one-star" rating, which means you are asking for only the severe cases. (not 2-star~4-star)  This is a tough one because I have rarely given 1-star. There are lots of people who annoy me but I take a star or two off in most cases and never a 1-star.

Few instances that I remember are, of course, the drunk and puke scenarios. Those are pretty much automatic 1-star. Another example are the real rude ones who treated me with disrespect, yelled, smoked in the car, slammed the doors, etc. 

Again, there are lots of cases where I took stars off.  Like this one dude last week who didn't speak a word and didn't respond to any of my questions. There are also cases where the rider would get my car dirty (muddy shoes), making me wait, not knowing exactly where he is going, etc. These are people who didn't mean to be rude but...just ended up being rude. :)

There may be an overlap with this one.  It's a good thread.

https://ride.guru/lounge/p/as-a-driver-have-you-kicked-out-a-passenger-ended-a-ride-early-mid-trip

Rider who  entitled riders think they can eat and drink whatever they want in our car by eating,bringing their opening alcohol or plastic cup with a drink to eat and drink  on purpose in our vehicle and also smoking with no permission forgetting  these are our personal vehicles although I always asking them nicely to wait to open it until I drop them off but the riders don't care .The UberX,Select and UberBlack riders are over the limit especially who they are more than 4 or 6 and 7 passengers  instead of ordering UberXL or SUV they are forcing to load them if they are more than 4 passengers and don't care if we got pull over by the police and getting a citation which is illegal against the law . Also " unaccompanied minors "  under 18 and  Uberpool riders who call me asking what's going on and where to meet while I'm waiting at the pickup point  which its also illegal for us to just pull over the curb and I get a tickets for stopping at the street or at the intersection and riders don't care .

Being annoying in general.  Not picking up the phone when I call.  That's a huge pet peeve of mine. I mean, I know you have the phone with you. You just ordered the ride. How can you not pick up from your driver?

In the couple of thousand rides I gave a 1-star only once so far.

Request came through with an already marginally rated passenger, but I took it anyway

Car packed of millenials, one (who set in the front) put left leg over the right with the tip of his dirty shoe rubbing on the interior of passenger door panel, making it dirty. Then he started playing with my A/C settings which I immediately (without saying a word) changed back to what I had it set to (hopefullt sent him a message). Then he reached for my personal tin can of mints and opened it up, I only had a couple mints in there so he put it back without taking any (I actually wold be happy if he gulped all the remaining mints I had left to take care of his dragon breath) and I would actually open up my reserve tin can for him too, I certainly do not remove starts from dragon breath passengers. He obviously deserved the one star.

If his rating drops low enough, good luck getting picked up by drivers who review passenger rating prior to accepting the ride.

Well, 3-star rating is pretty bad as you (the driver) will never be matched up with that rider.  In a small town, this is a big deal! :)