Existentialism must be experienced, I don't think it is a conclusion, it is a revealing, a way of confronting the reality we confront everyday. JP Sartre has a great bit in his novel "Nausea" the main character suddenly 'gets it' sitting on a park bench looking at the roots of a huge chestnut tree:

"All at once the veil is torn away, I have understood, I have seen.... The roots of the chestnut tree sank into the ground just beneath my bench. I couldn't remember it was a root anymore. Words had vanished and with them the meaning of things, the ways things are to be used, the feeble points of reference which men have traced on their surface. I was sitting, stooping over, head bowed, alone in front of this black, knotty lump, entirely raw, frightening me. Then I had this vision".

The whole passage is quite extraordinary..
[twren.sites.luc.edu]