Why should you read by a plan, by design, and not random?

There are three ways in which you can read:

• Pleasure – “I like Science Fiction, I read SF books”;
• Random – “I’ll read everything; can I take it? OK, I’ll read it then”;
• Design – “In the next years, I’ll focus on reading only titles based on this criterion: …”;

I like the latter one best; it lacks creativity, it may shape you into something you don’t want to become, but I consider it better than the two previous ones; I don’t think you can become good at something by chance; solution? Pick a criteria and stick to it.