[click on picture to enlarge]
When making a website you should always consider the colours you use and how you blend them together. You should never mix and match colours with no co-ordination, it puts a lot of people off and as the infographic says, it can affect the persons mood.
I've learnt that choosing one or two main colours and then choosing different shades of those colours really works well with a website. This rule can also apply to anything. It's easy on the eye and the eye doesn't have to keep adjusting itself to different colours.