Feature-oriented software development enables rapid software creation and evolution, through incremental and parallel feature development or through product line engineering. However, in practice, features are often not separate concerns. They behave differently in the presence of other features, and they sometimes interfere with each other in surprising ways. This talk will explore challenges in feature interactions and their resolutions. Resolution strategies can tackle large classes of interactions, but are imperfect and incomplete, leading to research opportunities in software architecture, composition semantics, and verification.