Learned how to friction shift as a kid, haven't forgotten how, and still have friction on some of my bikes (commuter, recumbent).
I appreciate index shifting on bikes where I have a high workload, such as the tandem or the racer. I could function OK with friction in those situations (and did for years), but these days I'm glad I don't have to worry about trimming a derailleur when dealing with a stoker or in a tight pack or paceline.
That being said, one of the most annoying pieces of human-built machinery in existence is a poorly-adjusted index-shifting bike that shifts erratically, unpredictably, or not at all.
Here's a "thumbie up" from my ancient Suntour friction shifter.
