Having some doubt is healthy with many different ideas and beliefs to sift through as your way of finding what feels right for you personally.
"Can these things really be true"? "Can this idea or belief be my truth"?
"Is it possible to connect with the spirit world"? "Do Mediums really talk with people that have passed away"? Yes, they do!
For someone that questions this as a reality, often the only way to integrate the belief as their own truth is to experience the process either through a personal spiritual occurrence, or with the assist of a reliable medium.
An angry skeptic is a different matter. An angry skeptic has an intense desire to prove to anyone that will listen, that nothing is real outside of the world of matter that can't be physically observed. An angry skeptic will be completely annoying in their pursuit to convince others that it is nonsense to believe that there is anything left of us following the change of death. Just as annoying as a religious fanatic might be to the opposite extreme.
I believe that we are born knowing all about this interaction between the physical and spirit worlds . . .
and then . . . we begin to think!
We have experiences that cause feelings that do not correlate with what we knew while we lived at the spirit level. As a result, many of us push aside much of our inner knowing in order to deal with what we experience in the physical world.
When our human experience creates fear, anger or simple unrest, our spirit-self can become less evident to us, somewhat hidden in the whirlwind of confusion over what we knew to be and what we are faced with in our earthly condition.