Mcmaster.com is the best e-commerce site I've ever used

Maybe that's the core issue. How are people expecting to interact with the site?

I think when you're selling with an obvious B2B focus, the "value subtract" nature of a lot of consumer-targeting selling practices become clear.

There's no point trying to jump a B2B customer through a bunch of cross-sells and (poorly) related products, because there's a fair chance he doesn't even have the purchasing authority to add any of them.

If your search or filtering sucks, time is money, and they're going to go somewhere that respects that.

Maybe what retailers should be looking at is ways to break up the "browse" from the "focused buy" experience.

Instead of getting me in-cart for the browsing experience, build some external content. Instead of "here's a category of 3000 toys, start clicking", write up some high quality articles about different products, target markets, etc. with deep product links. Since you're curating the content, you have a chance to "conveniently" sort the products to promote what you want or whoever gives you a kickback for browsing customers, while not frustrating the "focused buy" customer with a deluge of EKTIBAQNN brand USB cable/fire-starters.

What in god’s name what!? How much business are they losing from that I wonder haha

They are very smart. And weird. During my final round with the CTO I was waiting for him in his office on a couch. The couch was in a living room-like area of the office. After a few minutes of waiting I turned around. The CTO was sitting there staring at me; I've no idea for how lone. I stared back, then said "hi, I'm moeymo1. Are you Mr. X?" We started the interview.

They are conservative because the owners "like getting their dividend check and eating caviar" I was told. Apparently they tried to expand internationally in the 1970s when an employee wanted to move home and start a warehouse there. It turns out "home" was Iran, and the warehouse and its contents were seized after the revolution. That apparently put them off international expansion for a very long time.

They can pay big bonuses like financial firms. I didn't take the offer because they were too odd. Years later I ran into a woman that used to work there. Apparently they are super, um, not nice to women, at the exec level. She left for Grainger.

That's what sub-categories are for:

/foam/packaging/wrap or /foam/sound-absorbing/countoured

Hardware isn't some special case to abandon hierarchy. Hardware is perfectly suited to neat categories.

The site dips its toe into categories, but goes no deeper than /foam, even though it clearly lists about 20 foam categories. Each of those can be clicked, but the URL remains /foam. I highly doubt this is by design.

You mentioned packing foam. What if you wanted to send a link to your colleague showing all the packing foam this site offered? You can't do it easily. The best you can do at first glance, is send them to /foam and tell them to scroll down to "packaging and shipping" where 7 sub-categories of packing foam are listed.

There actually is a way to get the link to packaging foam, but you have to use the search bar to type it in manually. But don't press enter! You'll get taken somewhere else if you press enter, you must choose from the drop-down.

Amusingly, the site search doesn't want to respect my search term. When I search for "pickles" it takes me to "picks and pullers". What it should do is tell me it has no matches for pickles, but offer a suggestion.

Anyway, all good.. it's nice and fast and no doubt much loved site for parts pickers who know the part they want.