Can taking Tylenol take some joy out of your life? Apparently it can, by 20%, according to this small study. The reason I'm posting this is to make you aware that things we ingest can influence our emotions and our brains.
Here is an over the counter "safe" drug that could reduce your sense of joy.
http://psychcentral.com/news/2015/04/14/acetaminophen-blocks-emotions/83491.html