Which unanswered questions interfere with one's connection to G-d and spirituality?

I had an interesting discussion with Rav Trievitz this morning. The issue was the importance of identifying common questions which concern people about Yiddishkeit. 

In essence we feel that there are two groups of questions. 1) Fundamental questions which everybody asks at sometime and which need to be answered satisfactorily in order to feel that Yiddishkeit is meaningful and to have a proper relationship with G-d.  These questions are basic questions dealing with the nature of authority and G-d relationship with us. They included things like free will, mesorah, rabbinical authority and conflict between science and Torah, Chosen People, differential roles of men and women and importance of rational thought and innate morality.  2) There are more esoteric questions which would be nice if they were answered but one's connection to Yiddishkeit and G-d are usually not dependent upon getting answers. Examples are understanding the dispute between the Gra and Chassidim, the Chazon Ish's view of how scientific facts impacted halacha, nature of the Mussar movement.

My sefer Daas Torah was written to provide the sources in a wide variety of topics so that one could understand the variety of legitimate views and at the same time be able to individualize hashkofa. It basically is like a self-service grocery story. In contrast my work dealing with abuse is much more focused on getting the correct answers.

What I would like to be able to do is to provide clear answers that most people would find meaningful and satisfactory -  to the fundamental questions -  instead of just providing a range of sources.

The first stage is to identify the most important questions. What questions interfere with spiritual development if left unanswered? You can respond to this post or send them as email (yadmoshe@gmail.com).