When we were younger and worked in fine dining we talked a lot about tasting menus, the importance of small portions, and palate fatigue. The idea was that each successive bite of any one dish brought diminishing returns in terms of the overall experience. The more bites we took, the less attention we paid to the food. Therefore, tasting menus with their succession of small plates must be the best way to showcase any chef's talents. If you only had a couple of bites of each dish, every course would be new and exciting, so the overall experience would be that much more intense.
Of course there are flaws in this approach. The main one being the assumption that we will stop paying attention. I have had the pleasure of eating many wonderful things, in many different places, and on the occasions when I lost my focus on my food there were generally two reasons. One, that the food was mediocre, not bad but not very exciting. The highs and lows always commanded my attention, although for very different reasons. The second reason had nothing to do with the food and everything to do with the company and conversation. Good or bad, it has the ability to pull our focus from what we are eating. I'm not sure how often palate fatigue actually came into play, although physical satiation can definitely put an end to any great culinary experience. While we've all eaten past the point where it is comfortable to do so, it only take a few post meal belly aches to teach us the error of our ways.
To me the perfect bite can be anything from a perfectly crusty slice of bread with butter and salt to the most intricate course in an expertly prepared tasting menu. It is perfect because it is transportive. It snaps my focus on to what I'm experiencing and makes me feel cosseted and indulged. It can be a hurried bite of a doughnut while I'm folding boxes, that makes me stop and appreciate the flavors and textures unrolling across my palate or it can be a hot, creamy bowl of chowder eaten on the beach with the smell of the ocean in my nostrils and the wind in my hair. A perfect bite can be anything that makes you stop and appreciate the moment because of what you're experiencing in your mouth.