Hello ... I replied to your other post about convincing your wife to take lessons ... and then I saw this post.
Regarding SAFETY ... I read all the accident reports in my monthly issue of AOPA pilot ... so that I learn from other people's mistakes ... and I've taken most of the ASF's e-Learning courses.
What I've learned is that Accidents aren't a SINGLE event. They are a series of little things that all add up to the eventual "accident". So, while you are planning, pre-flighting, flying, etc if there are things that are happening that just aren't right, then make the decision THEN to abort the flight, or turn around, or land, etc ... rather than CONTINUE "to see if it will improve".
I've cancelled a flight with friends on board during run-up because a few things had happened already (late arrival, engine running rough, etc) ... we had planned to go to lunch for a $100 hamburger. They were disappointed, but when I explained that my primary concern was safety and that I didn't want to let ANOTHER thing add to the small, growing list of things that were going WRONG, they understood. We ended up flying another day and the trip was UNEVENTFUL, which is what you want it to be. We all had a great time.
Hope this helps.
You can read about some of my other trips with friends here: http://www.cowygr8.com/category/trips/