Warning: The content of this post is shamelessly sexist.
Apparently, you can never have too much Lego.
If you buy any sets, keep the boxes: it ups their value on Ebay. (Not that the person telling me this will ever let me sell any).
Any shop that won't let you grope their mini-figure packets prior to buying is not worthy of your money.
A man will keep playing with Lego long after his child has grown tired with it.
It's a process thing.
There is no right way to make a ninja.
There is, however, an exact right way to make Hogwarts School.
The vital piece you need to complete Hogwarts School is always the piece that's missing.
It's about the building, not the playing with the building after completion. Of course.
Do not become attached to any creation you make for your child.
Levels of non-attachment should be in inverse proportion to the number of hours spent in creating said object.
Some people have a natural ability to manipulate small pieces of plastic.
This ability might actually be useful one day. (Please, let me know how).
Lego-addicts are born, not made. (No matter how hard their fathers try).
You can sort Lego pieces into colour-coded boxes all you like, but your child will dump the entire contents on the carpet as soon as you're finished.
Lego tables look great, but the floor is where it's at.
Lego is really (I mean, really) painful if stepped on with bare feet.