I disagree that geese are very aggressive, I think they are misunderstood. They actually make wonderful pets if you raise them right and spend lots of time with them. That's the key though, you have to spend a LOT of time with them especially when they are young. My sister and I raised 7 goslings from day-olds five years ago and we were outside interacting with them for at least 1-2 hours a day, every day. We've also had five other geese that were raised with significantly less interaction than those seven received.
The ONLY aggression issues we've had are when a couple of the girls are on eggs. Then they get territorial, and understandably so. Our girl African and Chinese' have always been extremely sweet, it was mainly Suzy our girl Toulouse, and occasionally the Embdens that were aggressive around the eggs. The boys are all great. Duffy the "head goose", a White Chinese, is a big sweetheart. He loves to "talk" to people and have snuggles. The other boys aren't too friendly anymore, but have never been aggressive.
We've been pinched a few times by the nesty girls, but never attacked by any of them, boys or girls.
They are good guard animals and will make a big ruckus when someone/something new in on the farm. Ours are in a pen so they don't chase off intruders (though they do chase the crows and ravens that try to steal the eggs), but you sure hear them when there's someone new.
Geese are awesome