A recent paper (ironically in Nature again) explains that negative temperature is a concept based on a inconsistent definition of entropy:

Dunkel, Hilbert (2014): Consistent thermostatistics forbids negative absolute temperatures:

• http://web.mit.edu/newsoffice/2013/its-a-negative-on-negative-absolute-temperatures-1220.html
• http://www.nature.com/nphys/journal/v10/n1/full/nphys2815.html
• http://arxiv.org/pdf/1304.2066v1.pdf

The authors claim, that if one uses a consistent definition of entropy (the one from Gibbs) negative temperatures are not possible. So you are not the only one that thinks negative temperatures make no sense.

A recent paper (ironically in Nature again) explains that negative temperature is a concept based on an inconsistent definition of entropy:

Dunkel, Hilbert (2014): Consistent thermostatistics forbids negative absolute temperatures:

• http://web.mit.edu/newsoffice/2013/its-a-negative-on-negative-absolute-temperatures-1220.html
• http://www.nature.com/nphys/journal/v10/n1/full/nphys2815.html
• http://arxiv.org/pdf/1304.2066v1.pdf

The authors claim, that if one uses a consistent definition of entropy (the one from Gibbs) negative temperatures are not possible. So you are not the only one who thinks negative temperatures make no sense.