On a different scale of simple pleasures, I finally discovered what was making the bedroom wing of the house smell like poop. You would think I should have been annoyed at discovering my husband's smelly basketball clothing still soaking in the tub of our guest bathroom, but I truly found great joy in solving that smelly mystery (the joy probably came from how humourous I thought it was that I had mistaken his sweathy clothes with a poop smell).
What simple things fill you with joy? Take pictures of them, write about them, share it with someone... it just makes the joy last a little longer.