"Why are you painting such a weird picture?"
Translation:Miksi maalaat niin outoa taulua?
Depends. If it's a short question, like "laulatko?", "tiskaatteko?" etc. they'd sound much better with pronouns. So, "laulatko sinä?", "tiskaatteko te?". Otherwise, I don't see that there's much difference, other than for emphasis, as you said. In spoken language it's common to include the pronouns, although they have different forms then, of course (e.g. "laulatsä?"/"laulaksä?", "tiskaatteks te?").