well, solid core isn't impossible to work with its just a pain in comparison to stranded.
Its a lot more difficult to tin the end of solid core wire with solder, it tends to be stiffer and less maneuverable, its more tricky to actually solder to points on the board, with thicker solid core you tend to get a heat sink effect as the wire sucks heat away from the solder joint and its used by the undead, as you can see above.
On the plus side its.............err.......................................easier to garrote people with solid core and its impossible to torture people buy pushing it under their fingernails and heating the other end with stranded wire
