Einstein was a slow learner as a child and spoke very slowly.
He was a great musician. If the whole “genius” thing didn’t work out, Einstein could have become a working violinist.
He could have been the President of Israel. When Israel’s first president, Chaim Weizmann, died, Einstein was offered the position, but he declined.
He married his cousin. After Einstein divorced his first wife, Mileva Maric, he married his cousin, Elsa Lowenthal.