This is an interesting point. Being self-deprecating in a relationship is averting responsibility in a passive aggressive way.

If both parties are self-deprecating and holding the position strong, the universe will implode. So one party eventually have to pick up the slack and wash the dishes that have been piling up in the sink for weeks. The relationship will move on with one party being the active one and taking care of everything, while the other using self-deprecation as a shield to stay lazy. Too often, the passive party is the man.

To be honest, I am culpable of not putting in enough effort in my relationship from time to time. Deep down, it's a childish wish that my partner would figure out everything in our relationship and all I have to do is to ride along. Well, this is NOT how relationship works.

If you constantly say "I don't care. You decide. I like whatever you choose" to EVERY occasion, you are not being easy-going, but offloading the responsibility of maintaining a relationship to your partner.