I’m an engineer. When you see something really badly designed and think “wow, those engineers are so stupid! I could have done a better job myself!”
Please know that we did think about it. It’s just that some guy with an MBA decides the schedule, and another guy with an MBA decides the budget, and terrible designs get released no matter how much we protest. I’m sorry we couldn’t figure it out fast enough and cheap enough, though.
And yes, we do mistakes all the time too. It’s just that we usually know about the obvious ones.