We all want to believe that we are smart, good looking, and good poker players, but in reality it's a minority of people who possess each of these individual qualities, let alone the whole package.
For intelligence we have IQ tests, for looks beauty pageants (well, for women only, and then who's discriminated against here, right?), but how can you find out how good of a player you are?
Here is my answer to that question:
If you are mostly surprised by how bad the players who win against you are, you're a bad player.
If you are mainly surprised by how bad the players you win against are, you're a good player.
If you can't tell one way or the other, you are a donk.
PS: Don't feel bad if you found yourself in the donk category. You are still a bad player, but have more fun, and most likely lose less money at the tables than the other bad players who are not donks