I am Mr. Ollivander, and this is the wand shop
When Harry Potter was picking his first wand and Mr. Ollivander told him "The wand chooses the wizards, Mr Potter". The same principal applies to dad hats. You don't choose a dad hat, the dad hat chooses you.
Dad hats are the best kind of hat. A good dad hat takes care of you just like a father takes care of his child. It is the bond between dad hat and wearer that distinguishes dad hats from any other hat, and ideally this bond should be no less profound than that between a father and his child.
If you want to know anything else or have any feedback/questions, please send an email through to firstname.lastname@example.org :)