It is very need to feel the bad times in your life. Basically after or among good and enjoyable time of your life, you must have bad time. Otherwise you can't feel the true meaning of your life that should be realised very clearly in one's life time.
Bad time is needed for many reasons.
1) You can know about true well wishers of you and be clear about the fake.
2) You can realise that the fight of your life must be fought by yourself. You have not to depend others then.
3) You can be clear about your wrong doing done in your life time by yourself.
4) Your belief on Allah/God may be firmly standed.
All of these can be realised/understood heavily during bad times of your life. That's why I think bad time is mustly needed in one's life.
591.507 SRY