One thing I really do appreciate about Google products is that I'm able to fully disable personalization. My Youtube homepage is completely depersonalized, because I went through their privacy settings and switched off everything. I can't say whether or not Google is still secretly tracking me, but my biggest concern is actually that algorithmic recommendations put me in a filter bubble. Google lets me turn off the bubble.

Amazon, by contrast, does not let me depersonalize my recommendations. Neither does Netflix. There was a period of several years where I would periodically go through my Amazon history and manually mark everything as a gift. This worked for a time, but abruptly stopped one day. I assume Amazon decided I'd marked too many things as gifts and my selections should be ignored.