When there's congestion, you click "Confirm," but in reality, the transaction first goes into the mempool to queue, similar to catching the subway during rush hour. Miners/block producers don't look at who you are; they only see who offers a more attractive fee and who is easier to bundle, so your transaction might stay hanging there waiting, while the price moves outside. In the end, you either get slippage filled or the transaction fails outright, wasting some fee. What's more frustrating is that the same transaction is just sitting there; if you want to cancel, you have to pay again, which can easily break your mood.

Recently, I've seen everyone interpret ETF capital flows, US stock risk appetite, and crypto price movements as tightly linked. Basically, when sentiment heats up, the chain gets congested first to show you. Anyway, I now only believe in one thing when placing orders: don't gamble on "just catching the congestion." Better to be slow, split the orders, manually monitor gas fees, or you'll just end up learning a lesson.