Sometimes when I send a transaction on the blockchain, I clearly click confirm, but nothing happens for half a day... Actually, it first goes into the mempool queue, like a courier stacking up at a transfer station. During congestion, it's even more obvious: miners/validators will prioritize packing those who are willing to pay higher fees, so your transaction either gets pushed to the back and waits slowly, or it gets stuck until it expires (wallets will show it as pending for a long time). I usually just run with a small position and don't try to compete; if it's urgent, I add some fee, or simply cancel and resend to avoid getting emotionally affected by a progress bar. Recently, everyone talks about modularization and Layer 2, and developers are excited, like celebrating the New Year, but users just feel one thing: when the network is congested, more people are queuing... Anyway, before I send a transaction now, I check whether it's "peak hours" at that moment.