I'm not very good at explaining those technical details, but the "queuing" in the mempool is quite intuitive during congestion: you click send, and it's basically throwing your transaction into a large waiting room. Miners/validators prioritize packing those with higher tips and more profitable-looking transactions first. The rest just stay stuck, and if they stay too long, they either get dropped or you have to pay more and resend. Basically, it's paying to cut in line. Recently, during airdrop season and task platforms' anti-witchcraft measures, everyone is competing like clocking in at work. The chain gets congested, and the first to break is this "time-limited task" mentality... I now prefer to wait until it's less crowded before doing anything, or test with small amounts first. Otherwise, fee anxiety is more tormenting than points.