As is the case with many English terms, the Germans prefer to use the word service instead of dienen. The term dienen can be traced back to the 8th Century, when it meant runner, messenger, serf. Dienen in today‘s German means to serve, to be helpful, to be useful.
Dienen, however, also implies – and this is what Germans hear – subjugation, to place oneself below the person being served. Germans feel a loss of independence, personal sovereignty, autonomy, when dienen involves focus on the individual needs and wishes of the other person.
In such situations Germans sees themselves almost as slaves, as imprisoned, as unfree. They feel that their free will has been put on hold in order to serve the free will of the other. They no longer have the say over themselves.
Dienen, though, can have a positive meaning in the German context – namely when individuals freely choose to serve a common purpose, which is to the benefit of all, a greater good.
This all gives us a sense for why Germans avoid using the word dienen and instead prefer the English term service or the German-English combination Kundenservice, literally customer service. Germans have no problem subordinating their freedom when it comes to serving a purpose they believe in: Einer guten Sache dienen.
They do have a problem, however: serving exclusively the needs and desires of another individual. Such phrases as Ihr ergebener Diener, your loyal servant, or stets zu Diensten, at your service, have died out in Germany, and with these phrases the thinking behind them.