(My apologies if this is in the wrong PC thread. Wasn't sure where to put it.)
I was simply scrolling down a list of search results on Youtube, with Adblock enabled, and Avast Antivirus installed. I was doing nothing out of the ordinary, but right when I reached the end of youtube's result list, and it automatically loaded another page of results to scroll through, Avast suddenly beeped and a screen popped up telling me they've secured a threat from Google's own servers. Now, it MAY be a false positive, but I haven't been too trusting of Google in recent years either. Situations like this have also happened on too many other "safe sites" to go unnoticed for me.
Simply put, while using your best judgement and not going anywhere fishy is a good precautionary measure for avoiding unwanted software on your computer, it doesn't always work. An extra layer of protection can go a long way.