Jaika went AWOL from the Jedi order because he felt like they were more interested in preserving the status quo than they were in actually helping people, which led to a fateful duel with his sister, which led to a hyperdrive exploding in his face.

Now not only does the order not trust him anymore, but he's blinded for life. He copes with the sheer awfulness of it all by constantly making terrible jokes about it to hide the furnace of indignant rage that resides in his heart.