Some time ago I bought a shoe rack and coat rack from IKEA. Shoe racks seem to be more or less compulsory in Sweden. Attaching the hat rack (hatthylla) to the wall proved difficult. Rawlplugs pulled straight out and a little investigation led me to believe that the wall is made of lath and plaster, with a thick layer of extremely fragile plaster.
This weekend I finally got round to buying a stud detector, locating the solid bits inside the wall and then screwing a large piece of wood onto those bits. At last I have something solid to attach the coat rack to!
Of course the bit of wood (nice solid birch) cost more than the coat rack, but at least they match.