If it's any consolation - it's not all your fault. In the process of evolution, men became hard-wired not to notice easily anything smaller than a wildebeest. Just ask @gpseymour - he knows all about this. So, if a subtle clue is smaller than a wildebeest, you won't notice it and you can't help it. That said... I am pretty sure your dining room is bigger than a wildebeest.