Coke vs. Pepsi, Tayto vs. Walkers, Cadbury vs. Galaxy. There are thousands of rival brands in the world, and we all have preferences for which ones we prefer. But consumer researchers from Duke University, North Carolina have found that having different brand preferences to your partner can negatively affect your relationship.

When couples have high brand compatibility (for example they both prefer Diet Coke over other types and brands) they report higher life satisfaction. When they have low brand compatibility (one drinks Pepsi, one drinks Diet Coke) they report lower life satisfaction and their different preferences can lead to conflict and resentment. It might not cause the couple to break up but, along with other factors, it can lead to trouble.
The researchers used brand preferences in soda, coffee, beer, chocolate and cars for their study.

Something to consider next time you're doing the weekly shop.