Why Hair cutter and not florist ?

First of all: Which renderer are we talking about? Every renderer is free to make its own choices about what to render and what to ignore.

Now if we are talking about the tiles you get by default on www.openstreetmap.org (often called "mapnik" although that is the name of the rendering software not of the particular stylesheet in use) then there are two possible explanations. 1.) None of the rendering editors cared enough about florists to create an icon and rendering rules 2.) There are more florists then hairdressers and rendering them would lead to a cluttered ugly map. Not sure which of the two is the real cause.

If we are talking about the "osmarender" tiles (again that is really the name of the renderer which is used by the tiles@home community to produce these tiles) then the likely cause for any unrendered feature is: "nobody made a nice icon yet". Because osmarender tiles are not aiming for maximal aesthairdressingetic pleasure but try to create a "mappers map" including as many features as possible even if the result looks cluttered sometimes.

In general you can try to get your favorite feature added to your favorite rendering by filing a ticket for an enhancement against the relevant component on trac.openstreetmap.org. But please don't be disappointed if it takes some time to include the new feature in the map or if the stylesheet designers that the map looks better without.