Many users, particularly professionals, prefer Boolean query models. Boolean queries are precise… This offers the user greater control and transparency over what is retrieved… Indeed, experimenting on a Westlaw subcollection, Turtle (1994) found that free text queries produced better results than Boolean queries prepared by Westlaw’s own reference librarians for the majority of the information needs in his experiments.
Introduction to Information Retrieval, Manning
I also thought Boolean query models allow greater control over the database, and so I could produce better results. It’s interesting.