I'd be hard-pressed to think of another feature I love and hate as much at the same time as the ren'py bubbles. I like their look, and how they help keep the reader's gaze much closer to where the characters are, rather than trapped down in the text box. At the same time, the technical implementation of it in the ren'py core is just about the worst system anyone could have possible come up with, and breaks all… the… time.