In its ruggedness and lack of concern to look comfortable or easy, Brutalism can be seen as a reaction by a younger generation to the lightness, optimism, and frivolity of some 1930s and 1940s architecture. In one critical appraisal by Banham, Brutalism was posited not as a style at all but as the expression of an atmosphere among architects of moral seriousness. "Brutalism" as an architectural critical term was not always consistently used by critics; architects themselves usually avoided using it altogether. More recently, "brutalism" has become used in popular discourse to refer to buildings of the late twentieth century that are large or unpopular – as a synonym for "brutal" – making its effective use in architectural historical discourse problematic