From the training literature we have available from the time, knights were well aware of all the advantages they had in a combat situation if they wanted to be. However, like all professions that stem from a nobility, there are ways this could be bypassed in a particularly nepotistic fashions.
A "proper" knight would be a devastating force somewhat like a tank rolling through an infantry squad. In order to bring the knight down, the peasants would need to take advantage of numbers, terrain, and the few weaknesses that a knight presents. It takes one hit from a "proper" knight to kill a peasant, while the peasants need to knock the knight down before they can deliver good killing blows.
The realities: Nationalism in Europe came in with the French revolution. Peasant levies didn't care about their Kings for the most part. Especially if they'd been raised for a war they didn't understand, for the petty reasons of a King they'd never seen, and probably only knew the name of as a bit of trivia. They were more familiar with their local lord, and they knew that he was pressured to raise them, and wouldn't hesitate to make their lives miserable if they didn't pay their dues and join him on the battlefield. Nobody wanted to be there, and even the threat of retribution couldn't hold an army together if they took more than 10% casualties. The possibility of battlefield looting -- and city looting in the event of a sack -- had to be kept on the table in order to provide incentive. The constant psychological assault that their lives meant very little in the grand scheme of things kept the peasantry in the mindset that it would be better to run and hide than stand up and defend their own villages. However, there were places where this wasn't the case, obviously, and in those places, peasants could easily take down knights. Especially if the next reality is the case.
Being a knight meant that you were a pretty wealthy person. Just like with all other wealthy people, you have people who 'made it', you have people who are dedicated to the lifestyle who were born into it, and you have people who take for granted that they were born for glory and that life is going to be good to them by rights. You also have people who just don't give as much of a shit as they should in order to keep the system up. Now, imagine trying to run a military where your leaders have fallen into one of the last two types. Sure, any individual knight could be one of those top ones, and be one of the kind who actually could take on 100 peasants with 10 knights. (Spoilers: They only need to kill 10-20 before those peasants start running to shit themselves silly from sheer terror if they are fighting a pitched battle) However, they still need a tactical command structure from which to base a sound plan of battle. If you get a glory hog on top who thinks he knows better by right of birth, well, it is what it is.
In summation: The people behind these titles matters way more than the titles themselves. Warfare in these time periods is far more interpersonal than in times before and times after. There are many more factors that go into whether someone can win than simply the training and the equipment.