Petrie is (comparably with Guido) my favorite character of the LBT franchise. Except maybe LBT I, where I liked him less. He and I share similar personalities, because I am a jitterbug too, sometimes I also speak in weird way, etc.
I like, when he thinks of many things as dangerous, and then, when it is necessary, overcomes his fear, and helps his friends in need. Jeff Bennet's voice of him is brilliant.
I also think, that Petrie could have something like Aspergers syndrome.