You may have seen Simon Sinek's TED talk, in which case you can probably complete this sentence:
People don't buy what you do; they buy ...
I recently saw a longer talk by Simon Sinek, in which he talks about leadership, what biology has to do with it, and a whole lot of other things. It's a very good talk, 45 minutes long, and chock-full of interesting thoughts and insights. But I found it really hard to summarise in a sentence or two.
