I have two kinds.
One of them is a really fast heartbeat (around 160 bpm), but it takes a lot of anxiety to trigger them.
I experienced this last summer when I unfortunately had to confront a maniac with a knife and talk him out of stabbing some old man who he tried to rob. If the palpitations had happened while in front of the knife I wouldn't blame anxiety, but it happened about an hour later.
I experienced the same palpitaions just a couple of weeks ago, when me and my family went home by car from the holidays which we had spent in a cabin in the mountains. The weather was terrible, it was in the middle of the night far from home, and it rained so hard it was impossible to see the road, ligtning flashing and parts of the road floaded.
Rapid heartbeat isn't very scary to me, as it is the absolutely most common symptom of panic attacks. I just hang in there and wait for the minutes to pass.
The other kind of palpitations I get is skipped beats, and they scare me the most. Sometimes they come in short runs, but most often it is just one. If my bloodpressure is high, from walkin stairs or exercising, they are especially uncomfortable, as the beat following the extrasystole feels a lot harder than when I'm at rest..