Jacob knew what he had done. He knew why he was running from himself.
When he laid down his head in the middle of the desert and God showed up, he wasn't ready. He wanted to get his life together and THEN come home to face God.
He erected a marker--partly out of piety, and partly out of fear. He didn't want to face God again until he was ready. But it wasn't that spot that made it holy--it was God's love for Jacob. Ready or not, here comes God.