The little things
One thing that separates great products from average products is that the little things are done right. Those tiny little annoyances add up.
But when you notice that a common problem has been thought about and fixed - even if it's just a tiny issue - that's when you can tell how much thought and effort must have gone into designing it.
Here's an example that I just came across and wanted to share. When you install Nest, there's a tiny spirit level built-in to help you keep it straight.
It's a tiny little detail - one that'll most likely only be seen once by the customer - but it makes getting up and running with their product easier.