Let's say you already have a good looking face. You decide you want to look better, so you're gonna chop up your face (surgery). The better you already look, the riskier that is, because you have less to gain and more to lose. Thus, a decision to do a thing is different for every person, because everyone is in a different starting position.
Another fun kind of logic matrix. Tests. There's 4 quadrants. If you don't know the true positive, true negative, and false positive, false negative rates, then a test can really mislead you. If something has a high false positive rate, and a quite low incidence in the general population you're a member of, then a positive result can usually mean you don't actually have what's being tested for. If I recall correctly, AIDS tests have this property for most folks in the USA.
I like to give tips that are useful everywhere, and making better decisions is a life long skill.