What makes a poem good?

In my unprofessional opinion, I think it's all about the delivery....a strong beginning, middle and end.  I also think it's a feeling you get from reading something that touches you, capturing your interest.

Well known poets often write in riddles, at least I think they do. If you can figure out what they are saying, it makes you feel like you are as clever as they are?

Needless to say I don't get much....that's why I stay in the shallow end with the kiddie poems:)