I also put carrots (chopped very finely) into my chili. I don't think it does much for the flavor one way or another.
I will also vary the ingredients - depending on what is available. The basics are ground beef, onion, celery, green peppers, tomatoes, kidney or chili beans - the seasonings are chili powder, brown sugar, salt, and pepper.
After I figured out that cumin was what made canned chili taste like it does - I never - ever - put cumin - in my home-made chili. I don't mind cumin in taco seasoning, though.
I have - once in a while - added a tiny bit of unsweetened cocoa powder.