streaky windows and parenting

Little Possum loves to clean windows, in the house or in the car. This is something we should encourage and hope will last for a long time :)
The windows may not sparkle completely, there'll be streaks and demarkation lines where she couldn't reach any higher.... but she has such a great time. She'll have a serious look on her face, occasionally she sticks her tongue out in concentration and she always looks really proud when she's done. So who am I to spoil that with a "Oh, but it's a bit streaky" or "You missed a bit". So I don't. I just enjoy watching her and hugging her afterwards.