There are many different motivations for working out but most if not all can be reduced to two different categories. Exercise or Training. What's the difference and does it matter?
"Did you get your sweat sesh in today?"
Exercise can be described as the workout you do for the benefit you see that day. This can be the endorphins, the stress relief, the calories burned or just to mark it off your list of things to do. I'd guess that the reason 80%+ of people that workout do so to get some exercise.
That's a good thing. We'd much rather see someone getting some exercise than sitting on the couch eating potato chips, but there is a much larger world of fitness out there that takes exercise and adds planning and purpose.
This is called training.
You may be more familiar with the term training in reference to a specific event.
"I'm training for a triathlon."
An event is more or less a goal and training is planned and adapted exercise to help you reach a specific goal. For example, a person goes to the gym 6 days a week to burn a set number of calories for that day. For what purpose do they want to burn those calories? Are they trying to lose weight? Are they trying to maintain weight? It could be because they saw someone else on Facebook say that's what they do.
Calories are not meaningless but they are far less important than most people think they are. What if that same person took 4 or 5 days a week and did some organized training developed to constantly improve their strength, stamina, power, and reduce body fat? What if they had a knowledgable coach helping them know when to push harder and when to back off. Wouldn't they better off?
I've written about the Problem with Group Fitness before, and maybe I was a little hard on the "exercisers" out there. The problem isn't that it's bad it's just that you could have better. This new year as you pursue bettering yourself think about a future beyond today. Think about what your life would look like 3 years from now if you were to follow a plan.