<human>: Border Collie, age 5 years.

She's a super softie if humans are involved. Rolls over for small children and generally can't get enough of humans.

However introduce a dog? Complete change. If there's a toy, it has to be hers; she'll take it no matter what. Treat? It's hers.

Strangely, when she sees a new dog, she gets interested and even gets low to the ground and sometimes even rolls over submissively. And then she wants to play with the dog. But 9 times out of 10 when the playing starts the other dog finds it too aggressive of play and wimps out and then she feels dominant.

She spent every workday from age 4 months to 8 months in petsmart playplace so I wonder if she learned she could dominate all the dogs in there and it just stuck? Can I train her out of this type of behavior? Right now it's tough taking her to dog parks since she'll go around stealing toys and if another dog is going for it she'll growl and/or nip until its hers.

Can you give me the gist of the text in a nutshell?
<bot>: Dog loves humans. Bullies other dogs and steals their toys/treats. Not sure how to fix it...