Well, sometimes I get a bit "stressed" with my songs organization. A particular case is how to tag most love songs. I always can't seem to find a genre that adapts nicely to what I'm hearing. Tags on internet (liked DiscoGS, for example) tend to describe albums and bands, but rarely individual songs.
Some songs are easier to classify than others: for example, "Creep" (Radiohead), is clearly "Slow Rock" for me.
I do know that this analysis is highly individual. One could separate love songs from sad songs ("Porcelain", Moby, which I happily tag as "Electronic"), some could tag according to the most prominent instrumental part ("Still Got the Blues", Gary Moore), others take lyrics into account (some seemingly love/sad songs are not talking specifically about love), etc. But I'm still interested to know how you analyze this.
However, there are some worldwide "classics" for my example: how do you tag "I Will Always Love you" (Whitney Houston), "Someone Like You" (Adele) or "Un-Break My Heart" (Toni Braxton)? The formal description of a "Ballad" doesn't seem quite right (although it's what I've been reluctantly using), "Pop" doesn't seem to do justice.
Some couldn't care less, but those of you who do, how do you proceed in your collections?