Looking back at the contract notes from the end of last year: I. Bull markets often have sharp spikes, and these spikes can completely wipe out the opposing positions (altcoins with 2x leverage or more get cleaned out). II. Stop-loss orders on full-margin high-leverage contracts might not trigger. Simply put, during a crash, there might not be enough opposing orders in the market to execute your stop-loss, leading to slippage or even failure to trigger the stop-loss. III. Market makers in the crypto space tend to widen the order book and reduce liquidity before a spike. When sell orders can't find liquidity, that's when spikes occur.