For myself, the answer to this question is "Not much". I've had so many spiritual experiences in my life (While in my 20's I saw "ghosts" and "auras" on many occasions, felt incredible oneness with the universe on a near-daily basis, and had expansive clarity while meditating that seemed bigger than life itself.) At the time it all seemed amazing and undeniably legitimate, but with life experience, professional training and insight gained through research, I've come to believe these experiences were usually a combination of wishful thinking, exaggeration and depression/anxiety (oftentimes with pot and alcohol also in the mix), and not part of some bigger spiritual reality.
This is in no way to say that I don't believe that spiritual things may exist, but for me, I can't say I would absolutely trust my own judgment if I were to experience something like that now, and I certainly don't trust the many experiences I had when I was younger as being undeniably "spiritual".