Have you noticed how often clichés creep into conversation? Consider 'at the end of the day' which means roughly the same as 'when all's said and done' or 'considering all the facts'. In other words, it doesn't really mean very much at all, like 'actually' or 'in fact'.
The bottom line to all this is that these clichés, hackneyed phrases and trite expressions are a part of our language and we’d be lost without them.
Incidentally, 'the bottom line' originally referred to the most meaningful part of a financial statement, and is apparently favoured by the American Republicans, while the Democrats are more partial to 'at the end of the day'.
Queen Elizabeth II used the expression 'at the end of the day' when opening a building in 1982, although this cliché has been bandied around since the seventies. Its most recent rise in usage could be attributed to the song from the very successful Les Misérables. “At The End Of The Day” is sung quite early on in what is a very long musical (and now a movie).
Cliché was originally a French word for a printing plate, made of wood, and later of metal. The plate was reused, hence it came to mean a phrase that is reused. The Collins dictionary defines a cliché as "a word or expression that has lost much of its force through overexposure".
Trite comes from the Latin for worn out and was used in the same way as threadbare or shopworn. Now it is most often associated with the hackneyed phrase.
Hackneyed comes from the London borough of Hackney where horses were bred and trained for hire. These horses were known for their lazy, comfortable gait, which led to their overuse. By 1500 'hackney' meant anyone who worked for hire and a hackneyed phrase is one that is overused like the horses.
The main reason we use clichés is laziness. We can’t be bothered to think up new descriptions, so we cover the same ground, repeat the same old hairy chestnuts, in one ear and out the other, time after time, ad nauseam, year in year out.
At the end of the day, the bottom line is, I could go on ... but I’ll spare you.