The role of the background in bosonic quantum statistics is discussed in the frame of a new approach in terms of coherent states. Bose gas is not the only physical situation where bosons are detected. In particle physics bosons are dealt with in a context where the number of observed particles is finite: here the relevant feature are the canonical commutation relations, which we shall show to be related to a Boltzmann-like distribution. A further case is Bose condensate in harmonic traps, where discrete spectrum leads us to predict a new critical temperature. All these cases are analyzed in the unified approach proposed, showing that all differences can be ascribed to the role of the background. ©2000 American Institute of Physics.