Piggies are such individualists! It also depends in which kind of frame you are keeping them. If piggies are living in a group of sows (with or without a neutered boar), then their main focus is inevitably the group and the many group dynamics. If you have a couple of piggies that you are around a lot of the time and do lots with, then they will become much relaxed and interactive with you.
I know and have known very laid-back sows and boars that didn't like being handled at all. Generally, boars are more laid-back than sows, and they tend to mellow more once they are past their teenage hormones whereas sows can get more cantankerous and particular as they got older. Sows are wired to live in a core group, reproduce and have responsibilites for the babies (their own and other sows) and the group. Unless a boar has got his own harem to play peacemaker in, he hasn't got many responsibilities, as the bachelor boars hang only loosely around the core group. That gives both gender a very different outlook. But additionally, you have amibitious dominant sows and boars who will do their best to rise into a position of authority and submissive personalities in both genders who are very happy to have others looking out for them. Some are very caring whereas others like to very much do their own stuff.