Here's a good article with twelve great quotes that Dave Stein has used over the years in sales, writing, speaking, and coaching. Here are a few to entice you to read the whole article and see how these quotes relate to business: "Opportunity may knock only once, but temptation leans on the doorbell." (Unattributed) Or how about this gem: "Some people are so far behind in the race, they believe they are leading. (Uncle Junior on "The Sopranos")
These are just a few really of the great quotes in the article. Here is a classic from Tom Bridges (now retired from Tacony Corporation) that he used frequently "If it was easy, anybody could do it". He would use that line when facing challenges. Now add your favorite quote that you use in your work.