Our brains are wired to not actually see shadows, but to notice how they define objects. Shadows tell us if things are soft, hard, round, or sharp. It's more important to our health and well-being to know how objects will affect us, rather than to draw them accurately.
That means we only sort of see shadows. They are so shadowy. Artists must learn to dissect the lights and darks of the world, and view shadows as distinct things. Things that have shape and boundaries. You can't draw something if you only know it's general vague description, like, "over there". You have to know the exact specifics of the object, which in this case is not actually an object at all.
It's not easy to do sometimes, but I have a simple method that always helps.
Just squint your eyes. With live observation of your subject, this is essential, but even with a photograph, squinting will dramatically increase contrast - and decrease detail - allowing the shadows to be more pronounced. You can see their shape and position easier by squinting. Try it!
I just looked up, and I see some cabinets (I'm in my kitchen). There are cabinets, knobs, drawers, doors, a backsplash, and a countertop full of kitcheny stuff. It's tons of information, and the shadows barely register. Even if I think specifically about them, I don't easily divide the whole image into basic lights and darks. I see way too many variations and details.
Behold the squint. Now I see 3 giant bands of darks and lights. The countertop and backsplash are far lighter than everything else, but I did not realize how much until I squinted at them. Now when I start drawing this scene, it will be way more easy to make sure I keep all the shadow areas dark enough to match what is there. Accurate shading in my artwork is the result.
Happiness comes from reaching your artistic goals, and the world needs happy artists.
I'll have another shadow insight for you next time, that helps you figure out where to look for them, and even how to invent basic shadows for cartoons or photo reference that has bad lighting.