There are people in my workplace (which uses Gmail) who willingly use Outlook to access it then complain about Outlook problems. Outlook is the biggest piece of trash email client software I've ever used.

At one place I worked at, it was OBLITERATING any mails from one particular person because of a completely unrelated filter I had. Email notifications from them would appear for a few seconds, then the email would completely disappear (not even in deleted, or in any filter folders). Everyone else cced could see the emails except me, and IT couldn't figure it out. I had to disable ALL my filters which trashed my inbox with stupid work circulars. Fuck Outlook.