Good design

Hi,

I just want to tell you that I find KhanAcademy to be extremely well-designed. I don't love math and whenever I have trouble with it, I'm like "Yep, it's time to Khan". I like doing the exercises here more because of all the encouragement the system gives. When I do something correctly, it plays a happy jingle that I've come to really enjoy. There's always this bit of endorphine when I hear it, because I know it means I did good (Pavlov's dogs effect;)). And when I don't manage to get the answer right, it's not showing any red crosses and "fail" sings, but a neutral, grey color, and a short text telling me that I was almost there and to try again. It's very good for me, because I tend to lose my will to do more exercises if I fail at one of them.

To sum it up, I want to thank the people responsible for designing this. You did a great job!

Sincerely, me.

PS. It took me a while to find out where I could give a positive feedback. Why is it so hard to tell someone something nice, and a lot easier to criticize?