This is the correct way of looking at it. It's about how the thought contributes or hinders your own success/happiness. If you were to find, empirically, that

This is the correct way of looking at it. It's about how the thought contributes or hinders your own success/happiness. If you were to find, empirically, that believing that you're not deserving of happiness is more likely to lead to happiness, by all means do that. But to pose that it is an objective truth is more likely to be a justification for why you're unhappy.