Bathroom themes

Because I have chosen dark and light grey/white in the bathrooms, I need to develop a colour theme to liven things up. I was thinking one theme for my bathroom, and another one for the guest bathroom. Bro wants blue in "his" bathroom. Not sure where he got the idea from that it's his. But I can go with blue for the guests. Blue shower curtain, blue towels, blue bathroom mat. For my own luxury bathroom I am leaning towards pink (I know what you think but it's mine!). Alternatively I can buy several mats and towels and have different themes in autumn, winter, spring and summer. All these choices that need to be made!