Not the application itself, no, but its configuration. Once I managed to screw up things by modifying the fstab: I forgot the (never used) fs_freq and fs_pass

Not the application itself, no, but its configuration. Once I managed to screw up things by modifying the fstab: I forgot the (never used) fs_freq and fs_passno fields in a new entry for /tmp. mountall et. al. are fault tolerant and mount the fs regardless, but not so systemd -- it decided best course of action would be to not mount any local fs. You can imagine debugging that was a wee bit hairy, particularly since it was a head-less system.