Google has built a ton of services, all of them accessible via one account. In fact, with a few exceptions here and there (YouTube, Google Search, Google Maps), you can’t actually use most of the company’s major services without creating an account in the first place.
Needless to say, it’s very convenient to have all these services under one roof. However, I’ve never felt 100% comfortable with one Google account for everything. Let me tell you why and what I do about it.