Forget passenger endorsements. That was folly. Passing the paper test is just for the permit -- if ever I do passenger, I'll need to learn on / test on a passenger vehicle. No no. That's not the direction I'm thinking about just now.
Ah, but Hazardous Materials. While not an appealing prospect, the endorsement will be valuable. Sweet Babboo has almost always worked in hazmat transport (except for his brief stint in regional bus driving).
Here's the thing, though. Learning what all those placards on the sides of those trucks stand for ~ yowza! Class 1 -- Explosives. Yah. (I'd swap the #1 slot with #7, but I didn't get to choose the order.) Class 2 -- Gases (flammable, poison, etc). Class 3 -- Flammable liquids. Class 4 -- Flammable solids, spontaneously combustible materials, and materials that are dangerous when wet. (Class 4 is my personal favorite for scope and strangeness.) Class 5 -- Oxidizing materials. Class 6 -- Poisonous and Etiologic (because the word 'infectious' just wouldn't do) materials. Class 7 -- Radioactive. (I told you it should have the #1 slot.) Class 8 -- Corrosive. Class 9 -- Miscellaneous Hazmat. ... You mean there's somethin' out there that isn't covered by 1 through 8??
Next time you're breezing by a placarded truck or 'waking' in its blind spot, think about that.