What isn't your strength, doesn't have to be a weakness for social work. While some of us have excellent communication skills, many of us are average in communication. But is still enough for a job in social sphere. And even if your communication skills, or your level of responsibility, is bad, you should never mention it in your answer. It's just too important You should rather choose a weakness that is not so important, or one that can be considered as a strength by some employers. To such weaknesses belong:

☛ Being over-friendly

☛ Being impatient sometimes

☛ Being too punctual

☛ Having your own opinion always

☛ Not being able to take decision independently