Phrase to describe an offhanded comment that has a big influence on another [duplicate]
Something like these?
- “Mighty oaks from little acorns grow”
- “A journey of a thousand miles begins with a single step”
It's not yet a saying per se, but the so-called butterfly effect is a modern theme popular in certain circles and commonly referred to in modern speech.
So, people sometimes say things like “the flap of a butterfly’s wings in Brazil might set off a tornado in Texas”