stick in the back of your mind
I'm watching a show named Shark Tank. The show is about entrepreneurs presenting their business to investors and asking for investment. Here is a sentence said by an investor after the entrepreneur finished the presentation.
Before you start, let me finish with one thought that’s gonna stick in the back of your mind. There’s only two Sharks here that have ever sold a company for over a billion dollars. It’s “B”. Everybody else is an “M.” Millions.
I have two questions:
1. What does "stick in the back of your mind" mean?
2. Why did he say "finish with one thought" instead of "finish one thought"? Why did he have to use the preposition " with" ?