The whole joke is that Consciousness is bad. In the first panel, the man, who can make a choice, chooses to eat something bad, while the pigeons, who are not conscious, are just eating. In the second panel, the man chooses to be with someone who is wrong for him, while the pigeons just mate. In the third panel, the man gets mad for no reason, while the pigeons conflict over space on a windowsill.
Life is a pre-existing condition