Can it be Prog if I like it at 1st listen

Maybe a really stupid question to all Progfans around, but might be a basic one: Can an album called a real Prog one, if I like it immediately at the very first listening? I came to this idea listening to the new OPETH output and I've to say, I liked it immediately, as well their previous one, which was in fact quite different from this one. I've to admit, I didn't listen much to their other albums although I've got them all in my collection, only once each and I found all of them not that captivating in the beginning. Although they still use the growling death metal vocals on the new one, I don't find it that much disturbing (although usually I don't favour such vocs). But overall it's very very versatile (maybe that's the reason I like it immediately). I'm currently trying to get into really experimental stuff like Captain Beefheart - Lick My Decals Off, Baby (uploaded by Joren,thanks!), Doctor Nerve -Skin or Centipede - Septober Energy, but although being aware that all that stuff needs definitely several listens for digging it, I've to say that those albums don't give me one tiny hint for another listening, it's just too far out (of my mind)! I like a lot of intricate music right from the first (or second) listen, but especially some really experimental and adventurious music just fails to hit my attraction. On the other hand there are really some  here around considering more or less pop rock bands (I'm counting most of NeoProg and many Art Rock ones as such) as Prog (with CAPS P) what I can't follow at all. To come to a conclusion:

I DON'T KNOW ANY MORE WHAT'S PROG OR NOT!