Seriously, there's nothing more disappointing than a great tune being pointlessly extended by another verse/chorus which breaks the 3 minute barrier.
Smells Like Teen Spirit is the main offender.
But there's also a lot of Death Cab For Cutie songs which are guilty of this, as there are Bat For Lashes and BRMC ones, too.
Supply me with more offenders and together we can push back.
I therefore decree that no song should be listened to if it is longer than 4mins and does not change significantly during its time on my laptop.