5 truths about Hakkai.
2. Gonou never had a pet. Hakkai understands that Jeep's affectionate and uncritical company is a luxury, more than Jeep's service, which is duty. He doesn't know that Jeep will be allowed to stay when their mission ends. He indulges and pets Jeep while he can, and Jeep reciprocates.
3. It is possible to manipulate the others so that Goku and Gojyo won't squabble and annoy Sanzo such that at any given moment the air will not be filled with curses, bullets and flailing limbs, but where would he get entertainment on the long and dull road otherwise?
4. Hakkai is, surprisingly, learning more about being human that Gonou ever cared to. Mostly these are lessons he is compelled to endure by necessity and circumstance, more often frivolous than not, but it's not a bad thing.
5. He doesn't want the journey to end. None of the others do, but they can't do anything about it. He, on the other hand, is the driver.