Just because you keep your door locked when you're home doesn't mean you're paranoid. Sweeping generalization.

We keep our door locked, and it's muscle habit for me to lock the door as soon as I've walked in it.

But, to be fair, if we WERE paranoid, no one would blame us after that time we had this random stranger walk into our house when it was open, realize they were in the wrong house, and walk back out.