Here are some popular products and services that I don't use (or try to avoid) and the reasons for doing so. Please keep in mind that this page doesn't imply everything related to the following are evil, or these are the only/most problematic products or services out there. There are worse, but I'm listing the only ones that I'm frequently asked about.
Facebook is built around the idea of collecting and monetizing personal information. Even if it were not, I don't find any real use of Facebook for me. I've never had a Facebook account.
See this Wikipedia article to learn more. I know Wikipedia cannot be a trusted, but you can find trustworthy sources there.
I used to have a Google account, not any more. Several reasons, some listed in my blog under the tag google. They mostly boil down to privacy concerns and the lack of freedom and control.
An important thing to avoid from Google is the Chrome browser, which is really bad to one's privacy.
NOTE: Google says it "never uses your data in Google Workspace core services for advertising.". That doesn't answer whether they involve in unhealthy collection and analysis of personal information for some other purpose. Anyway, if one must have a Google account, I'd recommend the paid Workspace account over the free one.
I appreciate the fact that Google lets you watch YouTube videos without a Google account and DRM. I'm even ready to pay for YouTube Premium if it won't get me tied to the Google ecosystem.
Coming back to posting on YouTube, I actually had a channel and a good number of viewership. But Google is always in control of what ads to show and which videos to recommend. Sometimes this is totally unacceptable. The ads might be featuring products that sound unethical to you. The recommended videos might be spreading misinformation or might be inappropriate in nature.
Of course, user privacy is a concern, but there are ways to watch YouTube without losing privacy. What is more concerning is the control the creator lacks.
I use them when I have to, but I always prefer asking people.
I don't use certain social meida platforms like Facebook due to disagreement with the way they collect and treat users' personal data. But even with ethical services, I generally avoid using social media due to some personal tastes and beliefs.