It is befitting to say that Ramadan is an intensive course through which man refrains from what is lawful out of fearing Allah the Almighty, and this with greater reason means that he should refrain from what is unlawful. As if Allah the Almighty gives us iron will in Ramadan by which we are able to refrain from what He makes lawful to us (i.e. food and drink).
The months of Ramadan are like the steps of a stair, by taking every step, you ascend to a better level and take a quality leap, and you do the same the next Ramadan and the one that follows in the next year till you achieve the purpose Allah the Almighty has decreed for us. On the other hand, going back after Ramadan to the way we are used to be before it, is a big problem, as it means that man does not get any benefit from Ramadan.
Man will go back to food and drinks after Ramadan on Eid, but is he able to keep refraining from backbiting, slandering people or sowing dissension between them? Unless you stay righteous after Ramadan you will not benefit from Ramadan at all.