I once heard a very humbling message titled; "I am off to Tarshish". The crux of the message was this, Tarshish represents my will, my own, my plans, etc. not GOD'S, and that at the end of that journey to do things just my own way is a one-way trip to the bottom of the ocean. In Jonah's cases, he was on the way to Tarshish because he outrightly did not want to see Israel's and GOD'S enemy in his opinion, saved, why are you on your way to Tarshish?