I fed some in our local park, a few years ago, whilst walking the dog. After that, they would follow me, but only if I had the dog with me.
I was in Australia last year and was feeding some cheeky little black and white, starling sized birds and soon had a crowd of them, they even came on the table and waited for me to toss crumbs. They got quite aggressive when people came by.
At some point, two women sat down and said, "Wow! You're the Magpie Whisperer!"
I thought they'd be big birds, like European ones.