Clutch splines that fret themselves to death if not lubed annually/frequently (or 20K or so), weak as water alternators, cheapo Wherle diode boards, cheap-o Valeo (French!) starters with GLUED magnets that come unglued and can't be rebuilt, the $2000 O- ring kerfuffle, some sorry assed pfenning pinching accountant axing the 25 pfenning groove and circlip that hold the big tranny mainshaft bearing in place, the move away from taper roller wheel bearings at the transition to the monolever years, about 622 combinations of oil filters (hinged, non hinged, short, long) gaskets, washers, o-rings, etc., Bing CV carbs with short lifespan diaphrams....I could go on for several LONG paragraphs.
Still, when properly maintained not only will a BMW bike last a long, long, long time ( and frequently frustrate you every other step of the way), when they are in their sweet spot - none of it matters.
And lordy do us BMW folks whine. Yes, we do.
I think that there is a long term Euro consipracy here: BMW bikes MUST be designed by Ducati and assembled out in a shed behind the old Guzzi factory. That would explain both the Good - which is very, very, very good and the Bad -which is, well you know...