The one that always seems to pop into my head is 'Going Through The Motions'. Especially when performing the more mundane life tasks, hehe. Then it's always followed by I've Got a Theory or Walk Through the Fire- I just loved the songs where the entire gang were singing.
But I suppose..eventually I go through each of the songs, hehe. It's just they're so darn catchy! Case in point: Sound of hubby humming 'Walk through the fire' in the kitchen followed by him cursing to himself. Ah, the power.