If you find a person whose preferences aren't transitive, you can make infinite money.

Let's look at three preferences and call them A, B and C. For simplicity we define 'The person likes A more than B' as A > B. And we say that those three preferences are the ones that are not transitive. We can define them in such a way that this holds:
Furthermore, without loss of generality, we can assume that A, B and C have all the same monetary worth.
First we acquire A, B and C ourself. Next we gift that person the object A. The next step is to offer the person the object C and exchange it for A plus a small fee, which the other person accepts because they like C more than A. So now that they have C, we repeat the step but now offer B which they like more than C, and we can continue that and they'll accept because the preferences aren't transitive.