I think I am kind of lucky to be as uncultured as I am. It has meant at least that I tend to treat people of all kinds pretty well, judging the person, rather than their culture. However, a lot of the cultural generalisations exist for a reason too.
An interesting thought here: Could it be that the violence and thievery the Romani people in Finland display is a genetic trait and the environment enhanced it and those Romani friends you have, have the same deviant traits, but the environment they were raised in suppressed it?
Possible, but I don't think it is the case. More likely, if anyone was raised in that particular set of situations, they would be similar. And similarly, anyone raised in a different set would be different. My Romani friends are more like my other friends, because they have been raised similarly. And, there are people who are not Romani but spend a lot of time with them, and end up similar to them.
We are what we eat.