The GENRE tag field, introduced by ID3V1, was the first vehicle to combine a basic meaning or musical classifying along with the music file. It was only a one byte numerical field containing a number pointing into a standard textual list of musical categories (really bad sorted set).
By ID3V2 it is possible to add user defined descriptive contents by user defined tag fields.
So you can often find or just create yourself such tags like MOOD or MOODS, STYLE or STYLES, THEME or THEMES and so on, which allow to attribute the musicfile and give it a special musical profile.
As there is no closed official standard out there, you can find all variations of attributing musicfiles you can think of, so sometimes the mood of a song is even stored in the COMMENT field.
It takes some discipline to take care of a straight conceptional attributing design.
For example take a look to the allmusic.com website (e.g. http://www.allmusic.com/cg/amg.dll?p=amg&a...xkku3y5an1k~T0) and see what is displayed for GENRE, MOOD, STYLE and so on.
You may further search for a player or media library that can evaluate such tag fields, maybe can sort by MOOD values or filter all your files by the MOOD tag e.g on value 'Outrageous' or something else.