I think you do have some misconceptions.

You learn to appreciate yourself so much more, rather than attributing all your goodness and success to a higher being.

I don't find that to be true at all. We appreciate our life and accomplishments just as much, perhaps even more since many of our accomplishments have an impact that extends far beyond the lifetime of this universe.

Ultimately, the person you are today and the things you have accomplished are owed to far more than just the choices you made. You didn't do anything to earn the privilege of being born with your intellect and abilities; you could have easily been born mentally retarded instead. You did nothing to earn the right to be born into a time and place that allowed you to use those abilities to succeed; you could have been born into a war torn village in Africa and be dead before your 3rd birthday instead. There are many factors that contributed to making you who you are that were beyond your control and without which you would not be the same person. Acknowledging that fact by calling those things "God's design" does not cause you to appreciate yourself any less than acknowledging that fact and calling it "just luck".

For example, when I feel lonely or just not good enough in general, I don't ask God why he is doing this to me, what I am being punished for, or anything like that. I look deeper into myself, and try to figure out my problems much more introspectively. Because, I find that if you're relying on someone else to give you the answer, the process of waiting for that answer can be the most painful process of all.

I don't take either of those approaches since sitting around sulking is never the solution to anything regardless of whether you are conversing with God while doing so or merely analyzing your own thought process.