Do you judge a book by its cover?!

How many times have you heard this before?! So let's see, if it's true or not. 
I have been book blogging for 4 1/2 years, so have seen and reviewed a lot of books. I love my paperbacks, hence why I always look at the covers and think they somehow have to match in a series or with the authors. I always look at the cover and I adore the gorgeous ones. However, for me the important part is how it matches the title, the blurb and the story. 
These four parts have to become one in my opinion. It's only a complete book, when the blurb, the cover and the title match. Of course you don't know the story yet, when you look at a book for the first time, you judge based on the synopsis, the title and the cover, if you want to read the book. Of course the author can sell it to you as well, but only if you have read something by this author before. 
I actually feel cheated, when the title or the cover don't reflect on the story in the end. It's like something is missing and I got the wrong impression at first. Brilliant books can have terrible covers though and it doesn't mean the story or the writing is bad. It just helps selling a book. An attractive cover and title with a matching blurb can get a lot of attention for a book. Especially with series, I think it's vital to have them coincide and see a golden thread. I'm a beta reader for one of my fave authors and I actually see, how much work is behind this. We read the story first and start thinking about good backdrops and couples or people to go on the cover. We also look, whether the title works and then the author comes up with a blurb. It's great to part of this process and it does help to then promote the book like this. 
It's natural to judge a book by it's cover, I'd say everybody does it. I mean you look at the book and then the thoughts form in your head automatically. It's nothing bad. I think, one should just keep an open mind and always read the blurb or reviews as well. Even if you don't like a cover, the book can still have potential.