#1 - Norton Malware. . . .er, I mean "Antivirus" - had this installed on my family's first ever desktop computer, and it couldn't be removed! Tried Windows uninstaller, tried Norton uninstall tool (that's for when nothing else works). IT DIDN'T COME OFF! Eventually the hard drive in this computer died, so we ended up getting the hard drive replaced and a fresh install of Windows XP. (This was back around 2008, before I knew much of anything about computers.)
#2 Avast Malware (Antivirus) - it just simply doesn't work
#3 MacAfee - not as bad, it actually does work, and removes itself when asked, but last time I used it, the interface was quite clunky.
#4 Candy Crush - useless waste of time game that Microsoft decided (in their "infinite wisdom") to include on every install of Windows 10
As you can see, I have had bad experiences with Antivirus products. I currently just stick with Windows Defender, as it seems to work "good enough" and I generally stay away from questionable websites.