The dullest event in track is the 400. Not because there aren't great athletes, nor because it is inherently dull, but because it is sterile - eight runners in eight staggered lanes, where there is virtually no inter-play among the athletes, where it's problematic to even ascertain the relative placement of the runners as the race unfolds. When the the final straightaway is reached we can see how the runners are situated as they fight off rigor mortis over the final 80 meters. Only a little duller is the lead off leg of the 4x4 when the lead off athletes get three turn staggers to further obfuscate the race.
The 800 - the guys are elbow to elbow and tactics and racing skills in a pack keep things lively. Steeplechase guys are hurdling and jumping water barriers without lanes. Meanwhile, the 400 comparatively is like a postal competition: no fun at all.