I've seen worse
Mild praise given to something one has seen or experienced. Sometimes used ironically to indicate that something is actually quite great or remarkable. A: "God, what a terrible movie." B: "Oh, it wasn't so bad. I've seen worse." A: "What a stunning view!" B: "Wow! I've seen worse, that's for sure!"
(I've) seen worse.
a noncommittal and not totally negative judgment about something or someone. Alice: How did you like the movie? John: I've seen worse. Bill: What do you think about this weather? Gladys: Seen worse.