You cannot think your way out of true depression; you cannot think your way out of an anxiety disorder; you cannot think your way out of psychosis; you cannot think your way out of grief. In these states, the brain does not have to ability to "decide" to be another way. It's painful and insulting to tell a person in such a state that they must will their way out. You would not tell a person with ALS or cancer or heart disease or any of the many horrible so-called physical conditions that can befall us to think their way out of it. You wouldn't dare. But when it appears to be "all in someone's head," it's fine to say things like "man up." "You just have to decide not to let this get to you." "Just push through it." I do not mean that there are not things we can do to change certain states. Yes, sometimes various forms of exposure therapy, formal or informal, can reduce a terrible fear. Sometime when a fear is directly related to a particular behavior, repeated exposure to that behavior can reduce or eliminate the fear. Sometimes focusing on what we love or can do well can shift things. Of course. I'm not talking about that. I'm talking about a far more global state of depression, anxiety, or other mental or mood conditions that cannot be changed behaviorally. I have been there. To be told that "you're not trying hard enough" in such a state is the opposite of helpful.