As an anti-online virgin (first post), be gentle.

If your machine can be compromised by someone else's code, you're "owned." If the code is "supposed" to have a good effect but you didn't actively choose to permit the code onto your system, this is still bad.

Windows update? Fine. Even automated, this is acceptable.
Other automatic software updates? If you set them up, great.
Other people's choices? You're owned, and sooner or later you're not going to like it.