Recently I've realized that my cat gets very nervous, and even aggressive, if she hears me snorting loudly several times, even when she's a long way away from me.
If I start doing so, she immediately becomes more alert, moving fast from one place to another and, if I keep it doing for a while, she comes running towards me and tries to sit on me sniffing over my face and even putting her paw on my mouth.
She's never been in a conflict with another cat and of course we've never beaten her nor used any physical punishment over her. What might be the reason for this behavior?
---- EDIT 1 ----
Additional things about that I'm sure of: The position of her ears are straight, but when this happens she adopt a tense body posture.
---- EDIT 2 ----
Last night my girlfriend and I did some tests and, definitely, she finally gets very angry. When I started snorting she started being very active, running from one place to other, and even something she had never done before: rolling while face up on the floor. When I continued doing so, she started jumping from one chair to another and after awhile came over to me and I got a good chunk taken out. So, definitely, yes she gets aggressive and now I really doubt it's concern is what she feels.
Now that I have done this experiment, I determined some more physical details: the ears, as I said, were straight all the time except when she came to bite me, then she put her ears backwards. Her tail was in a "normal" position all the time she was jumping around, but when she attacked me, she raised her hackles.
I didn't want to stress her more so I didn't made any further try but definitely she doesn't like hearing me snorting.