Television, YouTube, and other sources present many images of singers hunched over microphones, squeezing their eyes shut, waving their arms, and essentially screaming. What are they saying to us? "See how much emotion I can put into this song? Watch me emote! Aren't I fabulous at this?"This type of singing can be called "presentational". It means that the singer wants to be noticed!
Is this what we want, truly? A large part of the listening audience today has been convinced that this is what singing is. What a sad conclusion! It plays well on television because we aren't there to feel the vibrations from the singer in person, to get the energy directly, rather than digitized, compressed, squeezed into a format that is easy to transmit.
Representational singing is a totally different experience, and is all about the singer wanting the audience to feel something. It occurs when a singer (a very young Frank Sinatra, for example) can simply stand in front of the audience and let the music and the meaning flow through him/her without having to "show" the meaning with extreme contortions. It is about the listener's feelings, not the singer's; about our reactions in the audience, not the singer's impression of what we should feel according to him/her.
Touching an audience this way, eliciting a tear or a warm glow or a laugh of recognition...THIS is what singing should be about. Our job is to allow the audience to feel what they need to feel, not to push our own feelings on them. If a song is well written, truly understood by the singer, and allowed to stand on its own, the responsibility we share as performers to the audience will be met.
Does this mean that we don't move? No. But a true artist, who lets the song sing through him/her, has little need for extreme gesture, no more than we use during normal speech to support our words. I urge you to remember that your responsibility is to your audience, not to yourself, and rather than being self-indulgent, let the song speak for itself.