The two produced buttons as well as coffee mugs , t-shirts , bumper stickers and many other items emblazoned with the symbol and the phrase `` Have a happy day '' -LRB- devised by PERSON@1 -RRB- .

The two used the `` smiley face '' on buttons as well to decorate coffee mugs , t-shirts , bumper stickers and many other things . They also used the phrase `` Have a happy day '' -LRB- which was the idea of PERSON@1 -RRB- .
