Whatever I liked, I suppose. My childhood pastor always said "doubt is the crucible of true faith".
Then I would say your pastor is a rare breed. Christianity is just not set up to allow questioning doctrine. Some denominations are more liberal in this respect, but no Christian sect or denom will allow the core tenets to be questioned. The payment for doubt is eternal torment and separation from all that is good. You cannot question that and remain true to doctrine. This is a core tenet of Christianity: belief or else pay the ultimate price.
So I'm sure there are myriad peripheral doctrines and matters of detail that can be questioned. No one but the most zealous and dogmatic will care if you think Jesus' skin was medium brown or dark brown or pale. However, it is a rare believer indeed who finds your faith true if you question whether he existed at all, or question the existence of heaven and hell, or question the existence of God.
Those rare sects and individuals are considered blasphemous by mainstream Christianity.
Some rare and small exceptions being Gnostics and perhaps sects like the Quakers, who have the audacity to respect autonomy and to hold that respect as closely as they do pacifism. Both these examples are considered heretics by all but the most liberal among mainstream Christians.
If you question whether God really loves the world if he sends people to hell for not believing the correct story about human sacrifice and eternal flame, you are going to hit resistance (or much worse) from all but the most rare of believers.
In my opinion, Judaism, in contrast to Christianity, is both a religion and culture that deeply values questioning and debate. However, ask any Jewish atheist who was educated in the faith just how far that questioning and debate is really allowed to go.
Allowing *some* questioning up to the point of protected dogma is not the same as allowing questioning. It's a pretense, the kind of hypocritical lip service that authoritarian social dominance ideologies like Christianity must engage in to thrive among so many millions for so long.