Just like updrading speakers

I have had two Klipsche bookshelf speakers for 2 years, and I have been happy without any regrets, but I have gotten used to this and lately feeling that I want more, so I am looking subwoofers, not with the intention of regaining lost excitement but something less drastic than that :-)
Then my thoughts drifted towards relation between two human beings and narrowed on socio-sexual couples(official-unofficial/married-unmarried); probably, even they may think in these lines, first starts with bookshelf speakers, years later surround speakers, few years later subwoofer, and then on one big day they stop listening to music all together.