Just kept watching the mempool, and it’s really like a delivery station overloading: you click "send," and the transaction lines up there first, miners/ordering nodes pick and pack based on who gives the higher "tip," and whose order is more suitable gets processed first; if you pay too little, it just stays there, and after a while, it might get bumped or you have to pay more and resend. The worst part is during congestion, you think it's already on the way, but actually it's just "collected but not shipped out."

Recently, with the cross-chain bridge theft wave, what I’m more afraid of is getting stuck in an intermediate state: you send it out here, but the other side is still waiting for confirmation, and the mindset is like waiting to see if the delivery gets lost. Also, with oracles occasionally reporting errors, on-chain systems prefer to "wait for confirmation" even more, everyone would rather be slow than receive dirty data.

What I’ve learned isn’t techniques, but: during congestion, don’t treat "submission" as "completion," it’s just a queue number.