Shipping is a feature. A really important feature. Your product must have it.

Usability is not everything. If usability engineers designed a nightclub, it would be clean, quiet, brightly lit, with lots of places to sit down, plenty of bartenders, menus written in 18-point sans-serif, and easy-to-find bathrooms. But nobody would be there. They would all be down the street at Coyote Ugly pouring beer on each other.

If something seems possible, that's probably because someone is already doing it. When something seems that it can't possibly work, nobody tries it. Real innovation happens when someone tries anyway, overlooking an obvious flaw, and finds a way to make an idea work.

So if you want to get things done, you positively have to understand at any given point in time what is the most important thing to get done right now and if you're not doing it, you're not making progress at the fastest possible rate.

All non-trivial abstractions, to some degree, are leaky.

Talk to your customers. Find out what they need. Don't pay any attention to the competition. They're not relevant to you.

The secret of Big Macs is that they're not very good, but every one is not very good in exactly the same way.