It is very difficult to tell whether or not someone is a good practitioner, but we can certainly see some signs in how a person behaves when she or he faces critical moments. For instance, in my opinion, when someone makes us angry or jealous and if we are not affected by it, then this shows that our practice is working, but if our emotions grow during such situations, then this is a bad sign and it shows that you still need to do your homework. It is we who should know where we are and our place in our practice, and if we pretend in front of others to be a good practitioner, then it is self-deceiving. Therefore, we need inner transformation, not outer transformation, because simply changing our appearance does not make us a good practitioner but only a good artist.

-- Zurmang Gharwang Rinpoche