Year after year you get the call for papers (CfP) emailed to you asking you to submit a paper which is sufficiently novel and which has not been published elsewhere. The "good conferences" get loads of submission, they go through a stringent process of review and the the committee sends out accepts and rejects. The registration of accepted paper, the travel and stay arrangements and finally the travel to the conference, presenting the paper (oral or poster), listening to the other researchers or keynote speakers and then back to work. This is an annual ritual, and if you are regular to a couple of conferences, then this turns out to be happening several times a year. Invariably the conferences are held in "tourist cities" and in most cases the most expensive venues (read hotels), giving one more (only?) reason to attend the conference. Rightfully, you see that the attendance is generally sparse (compared to the the number of people registered for the conference