Some examples of excess background:
- Tangents, side steps
- History that is important to you (when your company was founded), but irrelevant to the audience (unless you are a Champagne house that goes back to the 1700s)
- Preaching to the converted: spending slide after slide with data the audience is already familiar with, or arguing about issues the audience already agrees with
You are not giving a lecture in economics or history, you are trying to sell an idea.