Shiny happy people are the bane of newsgroups catering to cynics, misanthropes, suicidal people, bitter people, and the like (such as alt.life.sucks and alt.suicide.holiday and alt.bitterness). In this context, shiny happy people are those who show up and try to convince the rightful members of the group of one or more of these (non-inclusive):
We hate them. We flame them and watch them shrivel up and run away. We laugh and warm our fingers by the fire.