I'm sure science knows a lot more about how the brain works than I do. I've read quite a number of books about how we learn and how we make mistakes, but the inner workings of the chemicals and neural pathways are still pretty mysterious to me.
That leaves a lot of room for me to make stuff up about how I think it works.
One thing that I've learned about the body in general is the importance of exercise--and how if you don't use it, you lose it. I think the same works for your mind. My grandmother reads the paper everyday and keeps up with the news. She'll be 94 in February and she even still drives. You need to exercise your mind if you want to stay sharp.
It follows, then, that this would hold true for emotions and the positive or negative thinking that comes with them. When your brain sends a signal along a certain path that enables or encourages you, for example, to get angry, you're exercising that pathway. You're making it stronger and wider each and every time. With each new occurance, the signal is able to travel faster and faster--so fast even that you're no longer even really feeling anger, you're just recalling and remembering anger and starting the process. That can be dangerous because it removes you from the present. You're no longer evaluating the merits and particulars of the current situation--you're just releasing anger associated with other sets of memories.
On the other hand, if you don't let yourself get too upset over things, I fully believe that you kind of forget how to. Those neural and emotional pathways kind of wither and die. You get into the practice of remaining calm and instead of remembering anger, you remember stillness. Letting things slide off becomes your default reaction.
As an entrepreneur, its a form of training that could really pay off. My startup, Path 101, had a personality test associated with it. It really stuck me how much more emotional the average entrepreneur was than I was. I had no idea how other people did it--because doing a startup has a ton of ups and downs, and that seemed like an impossible roller coaster to ride if you were a really emotional person.
I think grudges and fights with friends are a form of exercising those negative pathways that people should seek to eliminate. It's fine not to like people. In fact, I think it's really important to have a filter for the kind of people you want to associate with in your life--and a lot of people should be falling short of that bar. However, when there are people out there that you genuinely like that you had a fight with, that's a bad pathway to train. You're basically telling your brain, everytime you have some interaction with that person, to harbor and feel bad feelings about them. Teaching your brain to have bad feelings about generally good people isn't the kind of exercise you want to be doing on a regular basis. It gets wires crossed and it really muddies the emotional waters.
Yesterday, I reached out to a friend that I had a less than fantastic interaction with the last time around. It had been bothering me how we left off, so I said, "Hey, I was disappointed how things went, but I do think highly of you and I'd love to get past this in some way."
It felt like dropping a load of bricks, as it seemed to feel for them, too. Getting back to feeling positive about positive people makes you feel like you've had a tune-up. Whether that's a business partner, an ex, or just a friend, think about the people you have actively negative feelings about and reach out. Maybe they'll be accepting and open, maybe they won't--but clearing that negativity out of your system, and ending the exercise of bad pathways will be well worth it.