ADHD characteristics
Some of the ADHD traits you have help you with your quest for fairness. For example: you might impulsively jumping into action when you see or hear something that doesn’t feel right. You don’t stop to think and wait until later when your energy or sense of urgency has dispersed.
Even despite having some traits would normally work against seeking fairness (such as getting social anxiety or debilitating procrastination) you'll still rise to the occasion, and do what is needed in order to right an unfair situation.
Your time
The need for fairness can be reflected in your career choices and it can influence how you spend your free time.
One of my client spent a lot of his spare time one year helping his neighbor’s child. The child had learning disabilities and needed help to get the right support from the school. There were meetings, long forms to be filled out and a lot of research to understand what rights the child had.
Even small pockets of your time can be influenced. For example, while waiting for people to be seated at the dinner table, you've probably already counted the number of carrots on everyone's dinner plates. Alternatively, at the last dinner out you had with your friends, it was probably you who reached for a calculator to make sure everyone paid what they owed and left the right tip for the staff.
The flip side
Unfortunately there are also downsides to being so fair.
You can feel powerless to make a difference as you are only one person and end up feeling completely discouraged and depressed about the world and its problems, the environment, the legal system, etc.
Standing up for other people can also mean you spend less time with your own family, and this can cause hurt feelings because ‘you put everyone else first’.
But don't take these to heart - most people find it very refreshing to be around you because of your desire for fairness.