I am very decisive. I'm constantly (over)thinking and (over)analyzing so when it comes to making a decision, chances are I've already thought through all the outcomes and trade-offs. My brain doesn't know how to relax or shut down.
All of that happens internally, though, and I don't generally announce (when that has to happen) my decisions until I'm at the end of that processing so it often seems from the outside like it's a snap judgment or an impulsive choice.
Things that don't need to be processed -- birthday gifts, groceries for the week, etc. -- because they don't have much long-lasting effect are my jam.
I have yet to do something impulsive in my entire life.
I'm currently at the very beginning of executing on a decision that I've been thinking about (literally) for years. I'm waiting on one more thing to fall into place before I start the dominoes.