There are, after all, shitloads of charities, all needing donations, and no one has enough spare income to support them all. Yet it seems like some are so extra special that unless you're visibly supporting them, you can get harassed for it.
OK this is partly inspired by this thread, but I was also remembering a fuss a few years back when some or other TV presenter was seen on TV in early November NOT WEARING A POPPY and you'd think he'd shat on a box of babies or something... About the only other charity I can think of that triggers this level of near-bullying among the stupid is Comic Relief - anyone else got any candidates?