He has the quality of being unformidable. The guests are very relaxed on his show I find. Tim Ferris is similar. Contrast to say Sam Harris, who although very erudite, perspicacious and articulate, asks paragraph long multipart questions and spends around 50% of his air time talking. Tyler Cowen is a better example of a formidable interviewer, who keeps things quite short and punchy and is always a little lighthearted.