Dark adaptation (retinal sensitivity) and pupil dilation are two separate systems even though they rely on each other. A bright light on the retina triggers the pupil to close to protect the retina. Darken the environment, like walking into a dimly lit room from bright sunlit outdoors, and even though the pupil responds quicker than the retina, the retina's rods and cones are still saturated from the bright situation, and it takes longer to re-establish the chemical sensitivity of the retina.
David mentions the night sky looking darker after packing up under white light and driving for a while. This is the saturation of the eyes to a brighter environment not picking up the fainter glow. Wait a few moments, and the glow becomes visible again.
Now, Mirko, do your 'dinner' trick again, and then look at M22 or Omega Cent. again. Yes you will still see them, and make out the brighter individual stars, but you will not see the fainter deep core glow anywhere as effectively, regardless of the exit pupil that the scope/EP combination gives you. Your eyes are still saturated from the bright lights of the lounge room (like David's eyes from packing and driving). You will also notice the background sky-glow darker - again this is a tell tale sign that your eyes are still light saturated. Try to spy out the arms of M83 after doing the 'dinner' thing, and you just won't. You'll just see the core, and even then with difficulty.
I've also encountered the exact same curious phenomenon you mention, both coming out of lit room AND driving. But, it is an illusion, as David mentioned, as those more subtle details and ques are just not there if you stop to pay attention. Even a careless flash of your dim red light into your eyes will screw them for a short time.
Now, dark adapted eyes have their own pitfalls! Our eyes are poor performers at low levels of illumination. They saturate quickly if the image stays static for too long. This is a real problem with dim extended objects, and if you have a tracking scope, it is even worse. Our eyes are made to pick up changes in light, so look at a scene for too long (light or dim), and our eyes begin to fail to see detail - major part of why our eyes dart around so much. Through a scope, darting eye just does not do it. You need to introduce movement into the scope to giggle the actual image. This 'resets' the sensitivity of our eyes, and for a few moments we see even fainter detail that we missed out while the scope was still. A little tap on the scope to introduce a vibration is all that's needed. This is why I don't have my deep sky scopes with motors - the constant nudging lets me see more.
Still not convinced? Notice when you are panning for a new faint fuzzy how your eye picks up those really faint blobs of light? But then go back with a slower action and you just can't see it any more (the bloody most frustrating thing I know of in astro!!!
). Two things at play here:
first: You are using your central vision instead of your averted vision to pick up the faint fuzzy, so you are screwed once;
second: The action you are using to double back is too slow for our eyes to pick up the oh-so-subtle change in light, so screwed for a second time,
Then out of shear frustration, you just jar the scope while no longer paying attention to the image, and you see the blighter a-freaking-gain! And all you can mutter is 'Oh bloody bull crap!!'
Experience helps. But being human, I still get caught out and frustration taunts my hot latin blood...