At first, a goose will bend its head back slightly. This indicates aggression. If the goose then bends its neck out straight, this shows the aggression is increasing. If a goose is about to attack, it will pump its head up and down. Geese may hiss or honk as well if they are becoming aggressive.
Do not yell at the goose. It’s better not to say anything, as to avoid provoking it. You should also not make any physical gestures towards the goose. Do not kick, swing your arms, or throw anything at the goose.
If there are geese at a local park or nature center, encourage others to avoid feeding them. You could talk to a ranger at the park about strongly enforcing rules that prevent people from feeding geese. If you’re at a park, do not feed the geese. If you have young children, strongly discourage them from feeding the birds.