I went to see singer-songwriter Michael Smith (not the "contemporary Christian" singer of the same name--this Smith is probably best known for writing "The Dutchman," covered by Steve Goodman and many others) over the weekend. He put on a great show; his funny songs ("Dead Egyptian Blues" and a terrific one, the title of which I can't remember, from an adaptaion he wrote of "The Snow Goose") are very funny, and the serious songs ("The Dutchman" being among them) are truly moving.
He concluded the show by saying something like, "This is the last song. And then I'll do an encore." And everyone laughed, as he intended, but all I can say is: Amen.
I hate encores. They are the least spontaneous "spontaneous" act i can possibly think of. I've been to too many solid two-hour shows that turned into endless endurance tests when the encores just wouldn't stop. I'm thinking in particular here of k.d. lang--I actually had to leave during her third (yes, third) encore or I was going to be waiting at Penn Station the whole night. And I've been to too many mediocre shows that became worse when the audience felt it simply had to clap till the artist came back, as if it were rude not to demand an encore.
I like the Michael Smith method. Plan the show. Do the songs you want to do. And leave before the audience is sick of you.