The warm cuteness is a definite bonus and incentive--truly, all of the characters, even the main character's down-trodden sidekick, have their appeals-- which one can enjoy without the usual disadvantages of explicit fanservice (You know what those are, people peering over your shoulder, etc). The short length of the series (13) also prevents formation of heavy emotional baggage that threatens to choke viewers with angst; the characters' questions and indecisions are resolved in a timely manner, and the plot moves on in an unambiguous and clear-cut fashion so that the viewer never loses focus.