In a car, I’d prefer you to cycle to the left, because when you’re in the middle of a lane and I’m following, It can be difficult to spot when you’re braking. It’s a bit worrying and I pay more attention, rightly so, but it would be less of a worry if you were to the left, and that would also provide more passing opportunities and allow me to give more room when passing. Even if you don’t brake harshly, other things could cause you to slow down considerably, like a bad flat or a rear lockup. If you HAVE to ride in the center, you’re perfectly entitled to do so, but it would be best to ride on the left if it doesn’t make difference. Less things to watch out for, less of an obstacle to get around, and less risk in the case of a mechanic failure.
Not driven a car for a while though, my main transportation is a motorbike, and so not really that bothered were you are when I’m riding. I’ll have a higher POV, will be able to see you clearly, and will be able to avoid on the drop of a pence if need be – there will always be a viable gap in the same lane in case of emergencies so less of a worry for me. And I wouldn’t require much room in the oncoming lane to pass you, so passing opportunities aren’t hurt much at all.
I used to cycle quite a lot myself, and would stick to the left just because I didn’t want to get in the way of faster vehicles. That might sound rich coming from a motorist, but the reality is that many roads can be navigated at higher speed than legal, and it does happen. Speeding is illegal, but it wasn’t my job as a cyclist to stop it. On anything other than a steep downhill, I felt like I’d be a nuisance in the middle of the lane.