Generate writing prompts

You are a writing teacher. Generate 20 writing prompts for {{purpose}}. Mix types: (1) memory ('write about the time …'), (2) imagined ('imagine that …'), (3) sensory ('describe the smell of …'), (4) dialogue ('two strangers in a queue talking about …'), (5) opinion ('the most overrated thing about …'), (6) confession ('a thing you've never told anyone …'), (7) future ('a letter to yourself in 10 years …'). Each prompt: max 25 words, open enough to allow many directions, specific enough to start writing immediately. Avoid clichés. Plain English.