If there's one thing I hate, it's taking off another car by accident. So I try to avoid it at all costs, but of course that doesn't always work.
I like battling for position, but when I see a car is coming in from behind at a much higher pace than my own, I usually let it pass without much trouble. I often use my direction lights to sign that I'm staying at one side of the track so he can make a safe pass without confusion. Of course I could try to hold him behind me and defend my position, but what's the point? It will only make the faster driver more angry and in the end force him to do stupid things in which we both may go off.
However, when I see the incoming car is running at more or less the same pace (I'm faster in sector x, the other's faster in sector y) then I like a good fight. But, even though I do look around a lot and try to leave enough room for a fair fight, it frequently happens that I push it a bit too far in the heat of the moment. It's rare I take someone out on the entry of a turn, but it happened more than once I lost control on the exit by stepping too early on the accellerator pedal in the hope to stay ahead. When I'm on the inside it's usually just me spinning, but when I'm on the outside the car slides across the track taking the car on the inside with me.
Of course, it happens the other way around too. But although regrettable, those are just racing incidents.
And some people just choose idiot moments to place an overtaking maneuver. Like in Aston's chicane. With Patch S/T the chicane became a lot easier, but with the previous patch the chicane was quite hard if you pushed. I usually needed every inch of space the chicane offered, but still there were people trying to overtake through the chicane, either forcing me off the track, or both going off.