I used to put Super Mario Land and a Game Genie into my red Game Boy Chunky, turn on the Always Super Mario, Infinite Lives, and Walk Through All Walls codes, go into the bathroom, and play all the way to Tatanga on the toilet. Those were the good days.
I don't presume to think I can make a comprehensive list of general ups and downs for toilet seats (I'm surprised no one's made the obvious joke yet), but I can talk about good and bad experiences I've had with toilet seats.
The toilet seats in my dorm room this past semester were quite nice, in and of themselves. Normally I'm not all that fond of the U-seats, but these redeemed themselves by being shaped and angled quite conveniently for excretory purposes. However, they were virtually always tainted by the misaims of simpletons who couldn't be bothered to lift the seat beforehand (or flush, for that matter). I have never been a fan of standing (I have terrible aim), which is why the seat is such an important factor for me, but even I can figure out "Lift seat, lower pants, pee, stop peeing, raise pants, lower seat, flush toilet, wash hands." Most of the males in my hall apparently do not understand and/or care about that.
Not all the on-campus toilet seat experiences have been enjoyable, mind you. One bathroom in particular, outside the dining hall, is rather high on my enemies list. The seats are made from a rather poor-quality plastic, feeling cheap and fragile, and unable to afford the soothing cooling that only porcelain can bring. Worse, in one stall, the seating position is situated considerably higher than normal, and in addition to making it more unpleasant for my legs, which must stretch a bit, it feels as though the toilet, which is sticking out of the wall rather than the floor, will simply break off under my weight, and the cheaply made seat is accomplice to this discomforting thought.
Toilet seats in my own home have rarely been pleasant. Originally, the single toilet we had in the house -- an appealing sky blue color, made from classically thick porcelain -- was as well-suited to my lower body as could be expected, as far as my memory serves. When my late grandmother moved in with us (take note that she was not yet late at the time), we added another bathroom to the house, which, as one might expect, also brought us a new toilet, with its seat. This toilet seat, by virtue of the size of its counterpart, was noticeably smaller than its sky-blue brother, but this mattered little to me at the time, for it was still of ample size for me, and the sky-blue toilet was still there for me. Furthermore, the new toilet seat had a pleasant, furry cover (not on the layer for excretory use, but the outermost, decorative lid), and was rather comfortable to sit on simply for the purpose of pants-wearing sitting.
But one fateful day, seats began to fracture. Replacement seats were purchased from a home improvement store, without a great deal of thought. The new seats were larger, more elongated; made from carved pieces of wood, sealed with the manufacturer's sealant. The seats were more elongated than necessary, and so undesired contact could inadvertently be made with the interior of the toilet bowl, with no seat back there to prohibit such occurences. Furthermore, the seat was clearly not made out of a single piece of wood, but of at least three smaller squares glued together laterally. Before long, cracks between these pieces became evident, which also began to render the manufacturer's sealant moot.
The newer, smaller toilet had its seat replaced, this time with a stuffed vinyl seat. This was undoubtedly the worst toilet seat I can recall interacting with. Far from the cooling sensation of porcelain seats, this vinyl seat seemed to collect heat, and had an affinity for lower-body perspiration. Its sweat habit was certainly aided by the way the seat formed to the buttocks of the user, creating concave areas for sweat to pool. Alas, even attempting to switch to standing brought no relief: the overpuffiness of the lid meant that it would not allow itself to stay up, and hence the only way to avoid disaster was to lean forward and hold the seat and lid up with the free hand; not a pleasant experience. This became necessary, however, because the bathroom housing the sky-blue toilet of old, long past its glory days, was rapidly deteriorating, and no one seemed to care enough to clean it. I watched with a heavy heart and tear-filled eyes as the bathroom of my youth was slowly destroyed before my eyes, epitomizing the loss of childhood.
To make a long story short, today we have three toilets in the house. The sky-blue toilet has been put to rest, both in body and spirit. The bathroom that rose, phoenix-like, from its water-stained ashes, is home to a toilet with an even smaller seat than the second toilet. That one now has a new seat, still a bit small, but at least it's solid. The third toilet, of course, has the smallest seat of them all -- or so I am told, for I have not had the courage to try that one. I doubt I could ever pry myself free after sitting upon it, and that is a death I do not wish to die.