If you don't notice or aren't aware, it means that the adjective oblivious applies to you!
When we think of the adjective oblivious, it is usually in situations that involve being totally unaware of what's staring us right in the face. It can also mean being forgetful and absent-minded. The cartoon character Mr. Magoo is a perfect example of someone who is oblivious; his eyesight is so bad that he always gets himself into various scrapes and mishaps. For example, Mr. Magoo mistakes an airplane for a theater and instead of watching a movie, he takes a seat on a departing airplane!