Music you like but don't want your friends to know you like it
Disco era tunes -- About a quarter of that period's music gets my foot tapping and my mind flashing back to that time. There was the typical fare on the radio, the top-100 stuff. But then there was the whole second-tier stuff ... often better-quality and finer musically. (ie, The Bee Gees, in the early days, much of which is truly great material, but which wasn't nearly so commercially 'catchy' as their "hit" stuff.)
Of course, a good amount of that period's dance/disco stuff was garbage, even with the typical beat and the horns, harmonies, etc., that were catchy. Filtering through the chaff to get to the wheat is part of the fun, for me. All the more so, given that 40+ years (and the march of media) has rendered much of that era's good music to the back shelves of most sources, if available at all.
Of course, there's all sorts of really good music out there, genres that I don't mind that people know I like. (Indeed, much of it, many people today haven't heard a lot of the stuff I tend to like most, so introducing it to them brings a lot of satisfaction once they appreciate how wonderful much of it is.)
Singer/Songwriter music -- Much of it, back in the day, I didn't like. But, overall I think it was very fine. A great period, musically, from the mid-to-late 1960s through the late 1970s.
Vocalists -- I
love a good voice. Done right, matched with the
right tune, it can be mesmerizing. Particularly if it's a bit deeper (ie, contralto instead of soprano) and has great range. Love me a great contralto, for whatever reason. Peggy Lee, Doris Day, Sarah Vaughan, Anne Murray, Nina Simone, Bobbie, Gentry, Gladys Knight, Patti Page, Mavis Staples, Carly Simon, Rita Coolidge, Karen Carpenter, ... along with many contemporary contraltos such as Nora Jones, Diana Krall, Alicia Keys, Madeleine Peyroux, Sara Gazarek, Jules Day.