How can you tell if you're neurotic?

Most of us. Most of us humans have some neurosis (inner conflict) going on -- so being human can be the first clue! ;-) problems can develop when we use up so much energy holding down unconscious fantasies that there's little left over for enjoyment of life -- or all our time is taken up with defensive behavior. Relationships can suffer also. Individual psychotherapy can really help a lot in such cases.