old是旧，shoe是鞋子，as common as an old shoe表示某人“不摆架子；平易近人；不卖弄；不爱虚荣；谦虚的；对人友好的”。

【例句】
Although he is a famous writer, he is still as common as an old shoe.
他虽然是个名作家，却平易近人。

I hope that in others' eyes I am as common as an old shoe, simple and easy to approach.
我希望我自己在别人眼里可以是一个亲和、容易接近的人。