Mike doesn't take to rock and roll lightly. He doesn't like a lot of rock 'n' roll guitar players, he finds them cliched. He played me this riff and it was like watching him setting fire to himself. It was an extraordinary riff.

1. "take to rock an roll lightly" - does it mean he doesn't like rock and roll OR treats it very seriously?

2. "setting fire to himself" - does it have a positive connotation or a negative one? I know it has a figurative meaning, but I'm not quite sure what it means?

He likes it a lot.

If you were on fire, you would be very active, trying to put out the flames. Very involved. I think the sense is positive, even though the thought of being on fire is certainly negative. [Her rousing speech set the audience on fire = made them enthusiastic.]
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Hi. Thanks for the answer.

But doesn't it also say that he treats rock and roll very seriously?

I'd like to ask about one more sentence.

Mike doesn't take to rock and roll lightly. And by rock and roll I mean metallic, blood running through your veins adrenalised music.

--- OK, so I understand that Mike loves rock 'n' roll and this is usually very hard (metallic), maybe exciting (adrenalized) rock and roll that he likes? Is my interpretation pretty much correct?