In the real world, there are some rough glasses that as objects behind them go away, they (the objects) become more blurry, but when we stick an object just behind this type of glass, it's almost shown clear (also some materials has this property in their reflections, that's another question).
For clarification, I photographed these examples:
How do you achieve this effect in Blender with Cycles engine? (mine is Blender v2.82)