British English has many phrases for presenting one’s own work as less than it is.
I just threw it together: I worked hard on it.
It’s a bit rough: It is finished, and I am fairly pleased with it.
It’s only a first draft: Please be gentle.
I got lucky: I prepared well.
Oh, this old thing?: A reply to a compliment on clothes, even new ones.
It was nothing, really: A reply to thanks, even for a real favor.