I've some questions to/about Anglo-Catholics?

I'm not an Anglican myself. I'm from Poland and I go to a lutheran church but I'm interested in the history of your church and I visit it to worship with you guys whenever I'm in the UK, and I'm asking this question to get know my brothers and sisters in Christ better. Recently I started reading articles and watching videos on different Anglican groups. And what strikes me odd is how catholic Anglo-Catholics actually are. Many of you pray to the saints, believe in all of the Catholic Marian dogmas (like imacculate conception, the assumption etc.), believe in purgatory (at least in some sense), have more catholic or even orthodox views on soteriology etc. So my question is: why aren't you just roman catholic? What makes you stay (or what made you become) Anglican despite all these differences between you and the traditional Anglican approach? Which catholic (and not traditionally Anglican) doctrines do you personally hold to?