Detecting undesired interactions in aspect-oriented models is closely related to detecting undesired feature interactions. Aspect interactions can be broadly categorized into syntactic interactions, which can be discovered by analysis based on syntax, and semantic interactions, which require an interpretation of the meaning of models. Semantic interactions are very hard to detect and at the same time often require significant rethinking or remodeling of the aspects. We argue that more research is needed to effectively deal with semantic interactions in aspectual models and that goal models are a suitable candidate to reason about these interactions.