Here is a 2 step process to answer such questions -
1. Clarification - what does bad mean? Is it bad user experience, bad product design, bad / useless / unnecessary features.
2. Identifying problem - based on the above clarification, you have to suggest who is the predominant user type and why do you think it is bad. For example, in uber India - the safety feature is poorly designed because it doesn't clearly suggest the specific call to action, which could be contacting the police or general safety report during your drive.
Mostly, this question is asked to judge your analytical and product vision skills. And the follow up question would be - how would you improve it.