You're not a shite person as you characterize yourself to be. I could feel the stress you must have been experiencing as you drove with your wife & daughter with that truck right upon your arse. I've been in driving situations like that before & it's terrifying! Nowhere to run, nowhere to hide. Just a freaked out truck driver from hell.
As for your wife, I can relate. My ex-wife used to screech at me when I was driving & it made my blood pressure rise until my head felt like it would explode. Add the truck tailgating to the stress created by your wife freaking out, & I can really feel for you...not to mention that your daughter was in the car!
I part ways with you on the knife, my friend. If you know you have a tendency to "lose it" when that stressed, it's probably unwise to be carrying a knife. Please don't feel I'm lecturing you, because I can almost feel the stress you were under in that situation. I know I'm prone to suicidal ideation, & for that reason I don't own, & would never buy a gun. It's simple self-preservation. Time will get stressful for us both at some time (as they will for most everyone), but it's wise to make sure we don't have the tools handy to do something stupid because of emotions that will probably pass. Starbucks bottles don't count as lethal weapons, though.
Again, I'm sorry you found yourself in such a crappy situation. I feel really badly that you had to experience that terror & stress. Take care - I hope the feelings will pass.