Weirdly (I think), it started when I watched a BBC documentary about the rise of fundamentalist religious/conservative groups to prominence in the US (and the Middle East), and how the mobilization of those factions came to be used as a potent political weapon by a rather fanatical right wing in the GOP.
One the series highlights was the teachings of a guy named Leo Strauss at Univ of Chicago, who helped birth what would become the NeoCon movement, which grew up to be the Radical Libertarian thing that Nancy MacLean talks about in her book Democracy In Chains, as Republicans work at tearing down our traditions of democratic self-government in order to replace it all with plutocracy.
Anyway, the Perry Mason character is appealing because he's kind of an anti-hero. He's more or less always on the side of right, but he's willing to bend the rules and play a little in SmarmSpace to get at whatever truth there is be gotten at, and he's not above omitting a few details as he directs his associates in their tasks, and sometimes manipulates his opponents to serve his purposes.
Also - it's good to know what's motivating your opponent.
(from about 6:20 thru about 10:30)
There's also a sexual tension between Mason and his assistant, Della Street, which was hinted at pretty strongly but never addressed directly.
But then, more than 35 years later...