1. Asymmetries or depressions in the nose
2. Displaced implants or cartilage grafts, which can make the nose look round and bulbous
3. Nasal obstructions that lead to breathing problems
4. A nose that is too large or too wide
5. Inadequate tip projection, like a droopy tip
http://www.newbeauty.com/hottopic/blogpost/6777-top-five-reasons-patients-seek-rhinoplasty-revisions/