Delft Institute of positive design research

'There are multiple ways to design for happiness. One way is to (re)design the experience evoked by human-product interactions with the ingredients of pleasure, personal significance, and virtues in mind. This is also applicable to everyday products and services such as a coffee maker, a booking system, or driving a car. Designers can also aim – on a kind of meta-level – to coach people in living their life in a way that fosters well-being. Such solutions go into the direction of design for behavior change or coaching methods, like finding ways to express gratitude, reflecting on what went well on a given day, or doing good for others.'

http://studiolab.ide.tudelft.nl/diopd/
This suggests images of positive interaction on the design will influence and 'coach' their well-being. Having words that reinforce this would work as well.