I love stories told mainly in dialogue. It's a great way to explore subtext: what's said/held back/inferred. In 'Beginners' by Raymond Carver, we have a story told almost entirely in dialogue. Carver is a master at this, and of handling subtext.
Have a read and try short story using mostly dialogue. What can you show in the relationships between your characters and the stories they tell? Can you handle this in poetry? Try a Dramatic Monologue:
BEGINNERS by RAYMOND CARVER in THE WALL STREET JOURNAL