When you 'take the high road' - it means doing the right thing even if its not popular or easy.
Not to be confused with the Scottish Song The Bonnie Banks o' Loch Lomond - which no one seems able to really interpret in any case... But is a good tune to reference when you need to remember to 'take the high road'
If a person wrongs you, no need to go and seek revenge or let it worry you. "Take the high road" and let them take the low road. In the long run that person will have probably wronged many people and their reputation is tarnished (their road is rougher) - while if you don't let it bother you and stick to doing the right thing, life will more likely work out for you as you are not bothered by the negative stress and your reputation is better. Metaphorically speaking, like a High Road
(aka freeway / highway) the view is often better and you can travel faster, while the low road is slower and has more obstacles and traffic lights.
It's also the correct path to take to becoming what is also known as a righteous dude