My cat is a main coon so maybe I can help you. MC's have very particular character traits...almost canine in fact....for example they seem to be like guard cats, they hate the postman, in fact mine waits for the post to drop thru so she can start to attack it, they are very territorial, they are also very good hunters. Also another MC trait is they love to talk (cat talk of course)
Now anyone can say their cat does the above too...but Main's are also very big and stocky animals, they look fat but in fact they are heavy boned and long haired. Also their faces tend to be more rounded than pointy.
Maybe your cat is part MC???