This chapter discusses some issues and disagreements in current psycholinguistics. These include the relationship between working memory load, interference, and predictability in online processing and the relationship between production and comprehension. Some empirical differences between data collected by different methodologies (online experiments, acceptability judgments, and corpora) are discussed, with particular attention to the locality versus antilocality of interdependent items. It is argued that psycholinguists need to pay close attention to grammatical rules and conventions, in addition to the data of performance, when setting up their theoretical models. The chapter ends with a critical discussion of efficiency and third factors in Chomsky’s Minimalist Program.