Scotland has a great quote which goes something like 'Dinnae teach yer Granny tae suck eggs!'
Translation: 'Don't teach your granny to suck eggs!'
Don't try to teach people what they already know — in other words, don't be a smarty-pants. And the sucking eggs part? It's a reference to the fact that in olden days, elderly people often had fewer teeth and could only eat soft food like eggs. Thank goodness for modern dentistry!
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.
Information technology is a formidable enabler of freedoms, lowering barriers of freedom of expression and allowing the people to get a better grasp of their lives