content: Being massless is simply a result of not interacting with the Higgs field. You're already familiar with particles that are massless. Photons. Visible light.  In terms of heat and friction, temperature is a measure of the average kinetic energy of a body of particles. If you remember from science class, kinetic energy is mass*velocity^2. Being massless, this gives the particle a kinetic energy of 0 and thus it produces no heat.