When I replaced my front door, one concern superseded all others: it must be opaque. Percy had developed the unfortunate habit of staring through the glass before knocking, and he'd seen me naked just a few hundred dozen times too many. Okay, it was maybe four times. But it felt like a few hundred dozen.
And thus did I order an expensive "rain" glass that I did not particularly like. My door is now impenetrable to the geriatric eye.
Percy, for his part, has completely changed his behavior. Now he walks all the way around my deck and knocks on my back door. After staring inside for a bit, of course.