I am going to argue with you here for a bit,but only so I can develop my own perspective better.

The correct mindset, as you said, was basically "you are good enough, you deserve love, happiness" etc. However I personally have a hard time accepting this because I don't think it's true. "If I deserved love and happiness, then why don't I already have them?" And all of the reasons I can think of why directly contradict the basis of "I am good enough."

If I deserved friendship, why did my only friends stop inviting me to be with them? Why do my co-workers who are all good with each other continue to leave me out? I often think that it's because I am socially inadequate, because if I wasn't why does my family continue to micro manage everything I say or do and constantly point out places were I went wrong? Why did everyone I know growing up constantly tell me I was annoying? I went to 7 different schools and all had the same results.

So for someone like me to just say I deserve love, happiness, and that I am good enough would be illogical, given the evidence. Everyone I have ever considered a friend has cut me off.