Ignorance is Bliss ~
The more I think about it, the more I marvel at the meaning behind the phrase. Just the simplicity it implies: the less you think, the happier you are.
Probably why childhood is considered to be the golden age of anyone's life, and is to be cherished while it lasts. Not that you realise it until it has passed and you -thought- about it properly.
Of course I realise the merit behind possessing knowledge too, and am beginning to understand how flexible and stretchy the mind and your thoughts can become with it. However such possession does imply a great deal more attention on your part, not to mention the expectations from you by others once in possession of something as simple as Pythagoras's theorem:

I won't dare imagine what how much further -that- one can be taken... -_-
(A mere simplistic example really, it's just that my current subject preference for maths tends to steer me this way...)
But this endless cramming of "Knowledge" (yes, I question the stuff put into our supple minds in todays schools) really brings you to wonder whether we could have done without it. Every new addition just makes you think more, and has you get lost in the vast maze of your mind. Ever tried backtracking an hour long thought pattern?
Life. Thinking.
All this captures the attention, makes you obsessed with putting together this endless puzzle of life, which happens to have more than a googolplex of puzzle pieces. And you never get to just stop, and enjoy what is already there, what you have already put together. You'll never notice that rainbow in the corner, or the mesmerizing glitter of a speck of glass that has been front of you the whole time. All you care about is working out where to put that next puzzle piece of plain white.
Well there. I have lost myself in yet another thought. I suppose this is the cost of us being sentient.
Also in a way explains the phrase: "With great Knowledge, comes great responsibility."
...or was that 'with great power, comes great responsibility'?
Either way, "Knowledge is power", and there's no disputing that.
As for me? I think I still prefer that "Ignorance is Bliss ~"