Many people have trouble figuring out the difference between assertiveness and aggression in other humans. Sometimes we have the same problem trying to nail down our own motives or actions.
Aggressive behavior in horses sometimes manifests as pushiness; a lack of respect that invades your personal space or recognizes a cue but purposefully ignores it. At other times aggression is demonstrated by a horse that insists on not only having a vote, but veto power as well.
Specific characteristics of aggressive and assertive people and horses and how to respond to them.