@bob

There's multiple ways to formulate. What I like in the case of the one above (which I only half quoted) is that people reading it won't be focused on the negative emotion, because it isn't higlighted or emphasized in the message that's conveyed.

Full quote is: "I think it's rational to assume the best in other people because most people are pretty decent."

With "I think" he makes it personal, applying to himself and inviting the reader to ponder if indeed it is a rational belief.