Many people mistakenly believe that what they think, imagine or feel is as important as what they do. The truth is that, as the old familiar saying goes, "actions speak louder than words." Deeds truly are more important than thoughts.
While we may empathize with other people, we can never really know another person's thoughts, motivations, imagination, or emotional experiences. All we have to go by when forming opinions or making judgments about other people is the track record of their behavior, what they do or don't do.
Likewise, you know your own inner thoughts, imaginings, feelings and motives, but the only information other people have to go on when forming opinions about you is your behavior. And unlike thoughts and most other mental events, what you choose to do, or decide against doing, is almost entirely within your voluntary control.
That is, a person really does not have much control over the emergence of thoughts, mental images, and other conscious phenomena - they often simply happen or even intrude into one's mind (an especially important matter when considering OCD). But action, movement, and behavior are almost always under voluntary control (unless, of course, one is suffering from certain seizure disorders or problems like Tourette's) so it's a good thing that they are what matter the most.