Amazon is not about getting you to fill your purchase order with the parts list of your latest project. It's about trapping you and selling you things you didn't know you wanted.

What would you want Amazon to learn from them?

I'll second that, McMaster's site is a work of art, especially if need something and you don't know the industry name/term for something.

That's a good point. It's been many years since I ordered from McMaster and I didn't remember shipping always being overnight.

I know this is the third "me too comment" for this, but you cannot overstate how awesome McMaster Carr is for this sort of thing - they have everything. Massive amounts of information on the site, super fast shipping, reasonable prices. If you build stuff in your spare time and haven't tried McMaster-Carr, you're missing out.

I am taking notes on their website. Now that is functional design, stripped down to the core.