I think cinema mixes are conventionally around 30 dB between dialog and the loudest sounds, which works great in the cinema (both because there is less ambient sound, and because you expect really loud sounds in the cinema), but is pretty extreme at home if you don't have a proper "home theater" setup. That's like the difference between normal conversation and a lawn mower. If you're watching a movie at home and two characters are talking and then one of them starts their lawn mower, do you actually want it to be as loud as if you fired up a lawn mower in your living room? For sustained sounds I generally wouldn't want it much more than 10 dB above dialog (that's like running a washing machine) and for very peaky effects like gunshots 20 dB is probably pushing it for most people's living room setups.