I used to work in a software factory when I was young. Only one guy in the sales department used to approach us (developers) when he was preparing a demo for a

I used to work in a software factory when I was young. Only one guy in the sales department used to approach us (developers) when he was preparing a demo for a big client of a new development. He wanted to know what to avoid, what not to do, which dataset worked better for the demo. Today I remember him as the most professional salesperson I met.