Very easy, depends on the position you are interviewed:
for example, if it is a designer position, say your weakness is
(1) Less knowledge of the overall product architect, or the priority of the features from customer perspective
(2) Too concern on the performance of the code, always thinking to optimize the codes, ...
(3) Push self too much to complete taskes far in advance milestones (2 weeks or one month)
If it is a leader position,
(1) sometimes compromise to project management to stay with old architect instead of introducing a new one (implication: minimize the risk, time-to-market)
(2) a little upset/frustrated if others make similar mistakens again and again though already helped correct them before
If it is a manager position,
(1) Sometimes expect team members too much for own experience/skills, need to make plan and help their career development based on individual strengths and skill sets
(2)
...
pick one of these, or you can come up similar answers (somethings don't hurt you at all)
tons of strengths for a specific position, if you don't know, don't go for the interview cause you are not going to make it (if you don't know how to focus on the key points and influence the interviewer).