Do people really not like the yellow paint? I remember when I started seeing it in games I was grateful I no longer had to make wild guesses about which part of a monotone wall was programmed to allow me to climb it. I don't want to have to wander around an area confused and frustrated because I didn't notice the one arbitrarily chosen stack of crates that looks like every other stack of crates that will let me get to the next part of the level. The yellow paint is necessary when level designers start getting too cute about immersive details that don't allow any interaction. If you're designing a linear path in an open environment, you need to do something to indicate the linear path. It's the inevitable result of filling games with insurmountable waist-high fences and unbreakable doors and straight up invisible walls.