I love being prepared. I always like having the right tool for the job. My desk at the office is covered with spare parts and manuals, and my junk drawer at home is filled with cables and loose screws. And when I say junk drawer, I mean junk cabinet. I won't throw away something that could be useful later, which has me worried that my next TV appearance will be on Hoarders.
Luckily, I can't be judged for all of the goodies that I keep in my rogue's bags. One of my favorite threads on the official rogue forums is the Ganker's Kit of Ganking. It's a very robust list of items in WoW that can help you kill your targets and avoid being killed yourself. I find that we're usually so focused on our normal gear that we forget about all of the other items in our inventory that can make playing a rogue fun.