The style, spirit, and expression of any work are mainly captured by the tempo, so it forms a major part of the interpretation. There's seldom one “right” tempo, and it's more critical with some pieces than others. Choice of tempo can be subjective, based on a conductor's musical personality and taste; or it can be practical, based on his knowledge of performance practice, the acoustics of a hall, or the standard of an orchestra. Tempo is a means rather than an end. We all try to find tempi that make the music sound great. In the hands of a talented conductor, an unusual tempo can make listeners and even composers change their minds. An audience notices if a tempo's convincing rather than simply “right.” Luckily, most music lovers have open minds on the subject. As a listener I can enjoy a variety of tempi for a piece, provided I haven't conducted it for a long time. It's different when I perform it: I believe in my tempo with every fiber of my being. Conducting without this conviction undermines an orchestra's confidence and makes it hard for them to play together.