Do people really just start crying without realizing they're crying?
yeah... it can happen. Hard to explain but the brain is not really one thing, its a lotta things that work really good together but especially when it comes to stuff like emotions there isn't really unity, best example is the fight between rationality and pride, like when one knows they lost an argument but just doesn't want to give in.
In that case its pretty obvious for oneself cus they quite literally clash, but if its not a direct clash then the part of the brain that has more power (In this case logic and friendship or smth) just takes over and supresses the emotion part without noticing, then the emotion part starts the crying process without the main part noticing and then boom you cry without knowing why or when it startet.
Brain is scuffed and weird af. Hope I made sense