There are days when you just don't feel like doing stuff ... going to work, putting extra effort into a relationship, or in a priest's case, doing an inspired puja when he's sick, and it's an agamic temple, and the pujas must go on, much like the mail must be delivered. Everyone has those days when it feels like you HAVE to ... well, because you have to. There were days when I felt like quitting my job, but with 5 kids and a stay at home Mom there, it was dharma, whether I liked it or not. So in times like this, mature responsible people suck it up, and get the job done. Others fluff it off. Hey, I don't feel like doing the puja today, so I won't.
This is another difference between the east and west .... discipline and short term pain for long term gain (eastern view, working for a greater good for mankind) , or a more nonchalant attitude about it. (western, more individual freedom)