The terms dom and sub come from the world of BDSM. Dom is short for dominant, and sub is short for submissive. This isn't something I know a lot about, but broadly speaking, whether you are a dom or a sub depends on if you derive pleasure from control or allowing someone to have control over you. Its a way of describing where you enjoy being in a sexual power dynamic.
But I always think of it in other contexts. This will probably be a joke one day, but in all seriousness, I am a kitchen sub. Its not that I can't cook, its just that I prefer someone to tell me exactly what to do and take the lead. Its refreshing to know that I don't have to think of everything in this particular area of life. When people talk about enjoying going to the grocery store, I have no idea what they are talking about.
There is a term I learned of last year called decision fatigue. Its the concept that people in positions of power or decision often take pleasure in not choosing. Conversely, people who don't get to choose, understandably love having a choice. I don't know if this is true, but maybe this is why nice restaurants have a highly dictated menu whereas Denny's can literally make you Spaghetti at 4 in the morning.
We all get decision fatigue, so knowing where you want to decide is important.
I think its important to know what areas you are a sub and where you are a dom. Sexually sure, but I mean in the rest of your life too.
I know that when it comes to work and money, I am some kind of reluctant dom. I hate having people exercise power over me. I am a mediocre employee, but I am a highly motivated business owner.
On the other hand, I know for as long as I live, I will never lift a kettle bell off the ground left to my own devices. I just don't have it in me to push myself towards things like that. Thats why in times past I've hired a personal trainer. Just tell me what to do, how many reps, and when to stop. I want to not be in charge.
I know this sounds silly, but try it as a mental exercise. I think knowing where you want to be in the power dynamic can make you happier and also help you save your diesel for the right pursuit.