Subtle but unmistakeable reminder of what milk is for.

Slovak Association of Dairy: Teeth Discover milk by Jandl, Bratislava, Slovakia

Seeing a lot of these shopping bag ads, which are arguably 'social' messaging, insofar as they involve someone directly with the message - as if they endorsed it. This involvement is what the target viewer sees, rather than a 'naked' message.

Creative bag advertisement for children with autism

FedEx (note the wall graphic).

Fedex: USA-Brazil in Award Winning Advertisements

Another ad that dares ask the reader to think about its message.

Pilot resistente al agua.