Even before most people thought of him as a presidential candidate, Donald Trump became a household name thanks in large part to his hosting of The Apprentice and the "you're fired" catchphrase that came with it.
Both at the time and since, Trump became well known for his unusual hairstyle and spray tan. And while both never really stopped being the subject of ridicule, it's become clear that people have become used to his signature look because they immediately notice when he isn't wearing it.
In the case of his most recent public appearance, the difference was noticeable but small enough that it had people questioning their memories.