What is the best business advise you have ever received?

So I was going down my street lane with a mentor when I asked him about the best business advise he can ever give some one starting out an entrepreneurial journey?

His response was:

Focus on Customer Customer Acquisition before moving over to Custom Satisfaction
The problem with some upcoming entrepreneurs is 'Misplaced Priority'.
It's good to also focus on customer satisfaction but remember, you can't satisfy a customer that you have not acquired.

Thanks.