Not everything in life can be fully comprehended.
Love, beauty in nature, feelings of awe – these things contextualize life. What do you love? What is it like when you find something greater than yourself that is overwhelming to your core? Not everybody has these experiences but for those that do, it very much puts things – that is your life – into perspective – that is, contextualizes it, like a frame or a new background that highlights aspects of life that might otherwise be hiding.
Also, not everything is amenable to reason, and also empirical knowledge – gaining knowledge through your senses, while extremely important and the basis of most of the sciences, there’s more than reason and the senses as aspects of human experience.
Plus, when you consider just how tiny we are and how vast the Universe is, it’s amazing we’re able to understand what little we do; and how much more there may be than we may ever know in this lifetime or 100 lifetimes or 1000 lifetimes.
Carl Sagan, never fully declaring “what he was” but most likely agnostic going by things he’s said (in a “don’t know” / “can’t be known” fashion), nevertheless emphasized the awe and beauty and mystery of the Cosmos, making Astrophysics which was his scientific field of choice, also his playground and church for experiencing the sacred in his popular science teachings with the goal of inspiring wonder in people in the magnificence of all things, even if he did not name it beyond the emotions it evoked.