I agree that bold doesn't necessarily have a bad connotation. A bold color (which would be like a very vibrant color). Someone with gumption, sass, or "balls" as we might say which certainly could get you into trouble, but I think bold just assumes that someone is not afraid to "go for it,"-- to take big action. but yeah, there's a slightly different connotation than bravery/courage which imply a hero whereas bold could be applied to someone who is a hero or a villain, or just daring. I really like the word.