回答
こんにちは。
One thing leads another. というと、私が知っている使い方は、いろいろあって結局そうなった、ということをちょっと誤魔化して言いたい時に使う使い方です。
Well, I was walking towards the station to catch my usual 7 o'clock train, then I saw Bob at the coffee shop so I stopped and said hello, then he asked me if I was taking the traing and I said yes, then he said he was driving downtown today and could give me a lift, then I said that'd be great and we had coffee together and were just about to take off when Bob realized his car was gone, then we had to call the police and file a report, then I was with Bob until he was done with it then I ended up taking an Uber downtown instead and I was late for work, too. Darn, I shouldn't have said hello to Bob!
ってことがあったんだけど、全部言うのめんどくさいので、
Well, I was walking towards the station to catch my usual 7 o'clock train, then I saw Bob at the coffee shop so I stopped and said hello, then one thing led to another and I ended up taking an Uber downtown instead and I was late for work, too. Darn, I shouldn't have said hello to Bob!
って言っちゃう、みたいな感じです。