整日孤寂的“午餐盒人”

Lunchbag refers to loser or a person with no friends, doesn't "fit in" and does nothing right. These were people who brought lunch to school or office in a bag, then went off to sit and eat it alone because no-one liked them.

Lunchbag(午餐盒人)指生活中的失敗者或者那些沒有朋友、無法融入所在的環(huán)境而且經(jīng)常做錯事的人。這些人通常都自己帶著午餐盒上學或上班，午餐時獨自一人坐在一邊吃飯，因為沒有人喜歡他們。

For example:

Stop being a lunchbag! Come and join us for happy hour after work!

不要自己吃飯了，下班后跟我們一起去酒吧喝一杯吧。