The largest trading loss I ever took occurred about 4 years ago when the Bank of Japan intervened in the currency markets just after I took a trade. I sold the USDJPY currency pair with several lots shortly before the Bank of Japan intervened to suppress the Yen to protect exports. I not only got clobbered, I added to my position and held onto it until the losses became so great that I could no longer endure the pain.
Here we go again! The Bank of Japan has now begun engaging in verbal interventions in the currency markets because the Yen has been rising steadily for several weeks. Now, with the Dollar falling following the Fed's interest rate cut to 0%, the Yen is rising even against the Dollar. Eventually, once the verbal interventions are no longer effective, the Bank of Japan will once again intervene with huge injections of trillions of Yen to push the price of the Yen downward.