Well, I'm not going to write a dissertation on the subject here, don't worry. Just a few examples on how TV Commercials coin new catchphrases.
I'm only talking about UK commercials here as we see a lot of them in Ireland by watching UK channels on Sky.
One of the best known catchphrases would be "Should've gone to Specsavers" by the UK based chain of opticians. Everybody in the UK and Ireland appears to be familiar with this catchphrase. Here is an example of one of their ads using the well-known children's TV character Pat the Postman:
My current favourite has to be the series of ads for comparethemarket.com. I love these meerkats and am always trying to get the sound they make at the end just right ;) "Simples" is certainly becoming a new catchphrase fast, at least in myhouse... As these commercials are sooo funny, I will show you 2 of them:
And last but not least, here's McDonalds. Not enough with being partially responsible for child obesity in the Western World, McDonalds have also created an easy to remember slogan "I'm loving it". Very clever advertisining on their part:
More will be added as I think of them, so check back here often.