You come across things that are normally square and true and simple that aren't quite so and that's what makes them interesting, some of these things are on purpose, a definite decision my the architect to give the building a little moxy.
Some are the interplay between nature and building, a wall that bows and bend to fit the landscape of the cliff behind it, but then a builder, maybe an artist who has decided that this is the logical angle for this, maybe he or she was thinking of how the light would hit them, maybe he or she wasn't but somehow it's discordant nature is what makes it what it is, gives it interest.