The trick to watching anime (and having a semi-enjoyable time) is to think of the activity as no different than reading a book or watching a non-animated show (more normalized entertainment pursuits) — that's the biggest stumbling block for newbie watchers who're acutely aware of the stigma surrounding grownup weirdos that watch “cartoons” and let it color their fun-time. Really, the only significant difference between the three is how the story is conveyed: art/words/motion-picture photography. Even though most of the mainstream focuses quite heavily on the teenage male viewer-base, the anime medium has a fair bit of depth — even for more mature viewers, so it's not about a constricted subject matter or premise in particular (rendering the what are they about bit moot), and caters to just about every taste (suspense/thriller, hack-and-slash, fantasy, western, mecha, romance, day-to-day slice of life, adventure, horror, trope heavy shōnen, Sci-Fi, comedy, supernatural, and so forth). Guess that's what the fascination with anime is all about: variety is the spice of life and it's just an alternative (and historically non-traditional) source of entertainment.