These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Souichiro: So... Lady Gaga has teamed up with the aliens...
Growing the Beard: The first two to three episodes are admittedly pretty bad. The series starts to gain its footing after that, but doesn't really fully mature until Season 2. The quality gradually increases, right up until the finale.
Jerkass Woobie: Light. Sure he's a Serial Killer killing off celebrities but he's also being molested by Shinigami and the man he's fallen in love with just wants to see him executed. His Freak Out after L dies (while simultaneously being Nightmare Fuel) cements his Woobie status.
Also Aizawa within the space of an episode-he wants to violate Misa (though to be fair so do the rest of the taskforce), he got his own daughter pregnant, and it's revealed he pushed Sachiko down the stairs while she was pregnant with Light. Though in Aizawa's case it's because he's being possessed by Souichiro's ghost.
Also Near is a Shinigami and leader of the invading force that's conquering the Earth and has set Light up to take the fall.