Les Binet and Sarah Carter get a little bit angry about some of the nonsense they hear around them… like the mantra that 'mine is different'.

A few years ago, we were working on a leading financial services brand. Our main client contact there was a smart data analyst who prided himself on his intimate knowledge of the brand and its millions of users. The brand had started to show signs of stalling and our analyst client was charged with finding out why, with our help. We started looking at a number of key measures and asked him what was happening to the brand's market share over time. 'Oh we don't track that. This is finance – it isn't baked beans you know' was the reply. But when we did a simple exercise to construct brand share and compare it with share of voice over time, we could immediately start to see what was causing the brand's problems. And in fact, the pattern our simple analysis revealed was entirely to be expected from what research has consistently proven is common to all markets.

The analyst's reply reflects something we hear regularly – so regularly, in fact, that we call it the 'mine's different' syndrome. The symptoms manifest themselves in different forms. These are just a few examples from last month alone: 'my market's different' (someone claiming that pain relief brand choice was rationally not emotionally based), 'my country's different' (a client wanting a different ending on a global campaign), 'my users are different' (someone suggesting that people over 50 – i.e. 'old' to most agency workers – view a category fundamentally differently). Then there's, 'my culture is different', 'my region is different', 'my brand is different', 'this decade is different' and so on.

When something is this pervasive, it is helpful to explore why. There seem to us a number of reasons. Partly it reflects a human universal truth that none of us instinctively likes to be bound by rules. And this may be an even stronger impulse in fields like ours where creativity is an important part of the job description. As familiar as we all are with the growing evidence of our human herd-like and copying instincts, we also all want to feel different, special and individual. To discover that our pet food brand is actually pretty similar to other pet food brands, or that the ethically conscious buyers of our new small food brand actually behave very similarly to the long-established global brand leader can be hard to accept. It is also a reflection that many people are simply unaware that there are cross-market rules at all. As we have remarked before, as an industry we are very good at junking back data and continually re-inventing wheels.

But more important than the reasons for the existence of 'mine's different' syndrome is the question of why it matters. It certainly is responsible for a good proportion of the politics and subjective debate that blight our meetings and slow down our timing plans. But, most importantly, it matters because if we act all the time on the assumption that 'mine is different', rejecting similarity, we can never learn from what's happened before. And so we carry on making the same mistakes over and over again.

There is an important caveat here, of course: patterns can only explain so much. Marketing and communication by numbers would be a disaster. Creativity at heart is about breaking 'rules', not abiding by them. There are fundamental similarities to humans across all cultures but also important differences – which global communication needs to be attuned to in order to tread the fine line between cultural faux pas and dull lowest common denominator. The skill for us in marketing and communication is one of balance – managing this fundamental tension between difference and similarity, between pattern and distinctiveness. We always rather liked the way this was beautifully summed up by a teenage girl in one of our research groups who proclaimed: 'I want to be different – just like my friends.'