Time

- Wait!
-No, I won't wait anymore. You'd better hurry, or I'll get ahead of you.
This has a special meaning:
The boy (omg, a boy in my drawings!!!) represents time, and the girl, well, a girl. She's just sitting there and desesperately asks him to wait for her, but he still passes by her, and everybody elses, because time just won't wait for us.
So we'd better hurry