The bottom line is it afffects sales. Sales numbers are what drives the revenue for the website. If one's shopping experience is bad or frustrating they are more likely to spend that revenue elsewhere. Who's gone to get groceries to discover a huge checkout line, and in that moment decided to either postpone that purchase or comeback at a different time (to a different store)? The actual time spent shopping is bad here because the mechanisms (website issues) make it more time consuming to locate, look at previews (wait for pages to load), deal with funky color combinations, etc. Pre-testing the website would have been idea.

Another simple thing. When you click on a vendors store, you get taken to the highlight page of products, not the actual full store. This is so frustrating. How about a separate highlighted sales button for the vendor instead? If I click on store I want store, not a small list of items.

I gave the example of a grocery store earlier for a point. If you are going to the grocery store you want to view a particular line of food product, not just 10 or 12 items selected by the store staff or by the vendor. 

On connection speed, I have a decent connection (for my area). The website is painfully slow. I hate to imagine people with slow internet connection speeds.

The dust settled, thinking "what a fine home, at least for now" not realizing that doom would soon be coming in the form of a vacuum cleaner.