Pimples!

Ever had a pimple on your butt cheek? Plenty of restrictions sial! And the pain and sufferings you have to go through! Imagine sitting on the other butt cheek everytime you sit down, and always having the need to adjust yourself if it hurts. Sheesh. Therefore the moral of the story is, do not immediately take over the seat of another in the bus or MRT if you know that person have been sitting there for a long time!