But only the negative ions were good; positive ions were considered to make one migraine-y and grumpy.

My favorite ion bullshit product was the copper bracelet my FIL bought for his arthritis. Not just plain copper that they've sold people for many years, but IONIZED copper! I tried to explain what an ion *is* to him, but failed. He finally said "Well, it makes me feel better, so don't fuck it up for me by telling me it doesn't work!" He knew himself very well.