Why is "raw" honey thicker than the one you buy in regular super markets?
The raw honey at your farmer's market is likely unfiltered.


  Usually raw, unfiltered raw honey can only be purchased directly from
  the bee farm. Characterised by fine textured crystals, it looks
  cloudier and contains particles and flecks made of bee pollen, 
  honeycomb bits, propolis, and even broken bee wing fragments. Raw and
  unfiltered honey and has a high antioxidant level and will usually
  granulate and crystallize to a thick consistency after a few months.
  It is usually preferred as a spread on bread and waffles, or dissolved
  in hot coffee or tea. However, as most consumers are naturally
  attracted to buying and eating crystal clear and clean honey,
  unfiltered honey which looks cloudy and unappealing, is not
  commercially available on supermarket shelves.


Additionally, the pasteurization process helps keep the honey more liquid:


  A lot of honey found in the supermarket is not raw honey but
  "commercial" regular honey, some of which has been pasteurized (heated
  at 70 degrees Celsius or more, followed by rapid cooling) for easy
  filtering and bottling so that it looks cleaner and smoother, more
  appealing on the shelf, and easier to handle and package. ... Heating
  also slows down the speed of crystallization in liquid honey. ... you
  may also find raw honey that are unprocessed but slightly warmed to
  retard granulation for a short period of time and allow light
  straining and packing into containers for sale.


http://www.benefits-of-honey.com/raw-honey.html