Red labels on cold drinks can increase your thirst and blue labels on drinks trigger feelings of thirst being quenched.
In international martial arts competitions things which are red in colour where fighters are identified by a blue or red colour, the red fighter wins 63% of the time. Red appears to increase testosterone. It's well known that men react to women in red dresses.
Retail outlets which use a lot of blue are more likely to relax you into making a purchase.