Sometimes this question is phrased as, "What would your worst critic say about you?" It is important to state a weakness that is either a positive or a negative that you have overcome. This could include "not being assertive enough, so I took assertiveness training and had discussions with senior colleagues," "I used to leave work late but I have now taken steps to improve my work-life balance and try to finish on time," or perhaps "I take on too much work but I have learnt to delegate and manage others."