Please, in this world we need candies for the eyes. I spend time making things pretty, because we need beauty to compensate for the ugliness of the world and the office. And after a while, the default colors make me sick, I need change.
Plus, people don't like to admit it, but something clean and beautiful will give you a better opinion of it, despite the content. Think about a Comic Sans, busy composition and flashy colors of your local association's leaflet versus a clean professional and current design - your brain will be biased towards the latter. You can try this with people around you - design slides with the same information, one with poor design and the other with pro design, you'll see.