 Or despair in thinking that God doesn't love you. He's forgotten about you. He doesn't see you. He doesn't care about you. So why bother? God abandoned me. Therefore, I will give into this despair. That's another kind of despair that would be sinful. Now, it doesn't mean that temptations to despair are sinful because they're not. No temptation is sinful in itself. It's just a temptation.