If you have never experienced or observed stratification, then you may simply not get around much (in terms of social circles). It's not that strange, I cannot afford it either, I just made some chance acquintances, mostly through my socially far more capabele partner.
Class had become the most useful criterion to distinguish groups to me. It's not about guarding oneself explicitly, or avoiding interaction, but more in happening to frequent different kinds of sports/events, having different types of interest and being able to afford those types of hobbies. You won't see a working class person drive up to the club in his jaguar old timer for a game of golf and going for a Michelin star afterwards with friends, talking over a new investment opportunity. You see what I mean?
I come from the UK, which is pretty strongly stratified in terms of class (to my knowledge, the most stratified, at least historically). My observation was that, as long as you're straightforward and pleasant, people from all backgrounds are unlikely to dislike you if you come from a 'higher' social class. They'll have lots of ideas about who you are or what you're like, but they are mostly positive.
People from richer social classes, on the other hand, typically either dislike poorer classes for a variety of more or less obvious prejudices, or they dislike them because they project their own antagonisms, and thus feel disliked, then become disliked because they act 'guarded'.
My general basis for friendship is common interests and interpersonal chemistry. I think if people assume they have no common interests with people from different backgrounds, or they sabotage interpersonal chemistry by acting guarded, then they're cheating themselves.
Michelin star food is generally not all that much better than other food, golf is no different to mini-golf (aside from being less eco-friendly and less fun), and a jaguar old timer is just a particularly unreliable, unsafe and low mile-per-gallon Honda. Personally, I don't have much in common with people who define themselves by their career success, whether that's shown by fancy sneakers, or fancy cars.
The point is not whether or not the differences are meaningful, the point is the differences exist, and are reinforced by self-selection, conscious or not. Parallel culture if you will. You are right, it doesn't have to be hard to cross the boundaries, but that doesn't mean they don't exist.
My point is the differences are backwards. People think that they're disliked by others, but they're actually projecting their own dislike of others. This happens in hierarchical societies because the people at the top necessarily owe their position to the suppression of the people at the bottom, but since they like to think of themselves as nice fellows, they tend to push all of the emotions this entails onto the people they mistreat. So behind many of these stories of boundaries, there's usually somebody from a wealthy background acting like an asshole to some poor sod, all the while thinking they're just struggling with cultural differences.
If you have never experienced or observed stratification, then you may simply not get around much (in terms of social circles). It's not that strange, I cannot afford it either, I just made some chance acquintances, mostly through my socially far more capabele partner.
Class had become the most useful criterion to distinguish groups to me. It's not about guarding oneself explicitly, or avoiding interaction, but more in happening to frequent different kinds of sports/events, having different types of interest and being able to afford those types of hobbies. You won't see a working class person drive up to the club in his jaguar old timer for a game of golf and going for a Michelin star afterwards with friends, talking over a new investment opportunity. You see what I mean?