One if the ways i have judged people is by imagining how well they would get along with their own clone.
Its of course easy to talk hypothetically but i always felt we would quickly arrive at a mutual understanding that we must obtain an equilibrium at all costs.
Because they are not the same person so their needs, maturity and personality are different.
The person that made me come up with this is actually my sister (during a teenage phase). She would have hated if people used her own rhetoric against her.