" How did you get interested in something" use past did not do because the initial interest was in the past. The answer, 'I got interested in playing the guitar after I had listened to a famous guitar player' about "like" How did you like playing guitar is not the same as to get interested....... It is a past event, a personal experience or opinion You could say 'How do you like playing guitar?' if the person plays guitar in the present time. So the internet is correct Maybe you could use why with like Why do you like playing guitar? not the same as 'How did you get interested in playing guitar' but a person might answer these 2 questions in a similar way.

Here are a few other ways to ask this question with similar meanings: 1. How did you get into playing the guitar? ("Get into" means to become interested in.) 2. What made you start playing guitar (or learn guitar)? 3. What made you like playing guitar in the first place? All of these are friendly, polite questions that express curiosity about the person being asked, so most likely would be well received since most people like to talk about themselves. Hope that helps!