The GROUP BY clause of SQL queries is completely redundant. All of the information in it can be derived from the rest of the query. Redundancy in communication is a great thing for human communication, to prevent misunderstandings. It allows for error correction. But it's not a great thing when I'm hand-typing such a verbose language.
GROUP BY should be made optional. In some cases it might allow the SQL parser to detect an error I've made in my query. And in some cases it might be necessary (but so far I can't think of any). I'd probably want to leave it in to programs that I am going to leave lying around. But for queries I'm throwing into an interactive system, I don't want to deal with it.