For example I went to import some contacts today and was surprised that Mailchimp was unable to automatically correct basic syntax errors such as "usergmail.com", "user@gmail" or even "user@gmail.com <FirstName LastName>"
The fact that their product management team never thought it was a priority to include such an easy time-saving feature makes me think they have a rather hard-headed culture that is missing the boat on a lot of things. I can see why they would be difficult for Shopify to work with.