At WN we've had several crews climb with the take-off warning horn sounding. Didn't figure it out till the FA's called and told them the "gear" was down.
It's happened to every 737 operator out there. Why? Cause it's a stupid system. Who puts a dual use horn in an airplane? I mean really. We've got a box that can tell us to pull up. A box can tell us to go around. A box can tell us if we're going to hit somebody. Surely we can have a box tell us:
"hey dumbass turn the packs back on" or
"hey dumbass put the flaps out" or
"hey dumbass release the brakes before taking off"
Gup
There are a few other panels on the 737 that get confusing even for the seasoned 737 pilot.
If would have been great for an airplane with a Glass cockpit to have the option for messages on those Glass displays like every other glass airplane, but for the NG that is not the case. Which airline can we blame for that? lol
It is more about training costs and selling airplanes than safety obviously.