The toilet seat is a simple device used to suspend the user of the toilet about the grimy and soon to be very dirty in the bowl below. Toilet seats are usually made of plastic, and some are heated, so that rich people don't have to get a cold ass whilst shitting. Toilet seats, by necessity, have a hole in them for the excrement to pass through as it leaves the user's body and passes through space under the influence of a gravitational field.
Some toilet seats, especially those in public rest rooms, is not a topological torus, the front part of the seat being cut away, presumably so men can pee without lifting the seat.
The toilet seat, when attached to the toilet and the toilet lid, forms a finite state machine having only three states. The operation of such a simple state machine is often lost on women, who often have difficulty telling which configuration the toilet - toilet seat - toilet lid machine is in and consequently fall directly into the toilet bowl, often coming into contact with the grimy water residing there. This is a great cause of contention between the sexes, as men usually prefer to leave the machine in whatever state it is in when they finish, which is usually with the seat raised, and women prefer that the seat be down, so that they do not fall in when they forget to check the state of the machine prior to operating the toilet.
See I will REMOVE the fucking toilet seat if you don't shut up for further discussion of the topic.