Recently, looking at those on-chain transactions where "I just want to swap some coins, but the slippage feels like I got robbed," nine out of ten times it's not your mistake, but sandwich attacks + arbitrage queuing up to collect transaction fees behind the scenes.

You think you're seeing an opportunity, but more often you're just someone else's fee source... To put it plainly, that little "advantage" you have isn't even enough to fill the gaps for searchers.
Now, with staking/sharing security yield stacking being criticized as "pyramid schemes," I can understand: the source of the yield isn't clearly explained, and in the end, it's still extracted from trades and liquidity, and the more complex the path, the harder it is to see who is paying.
Anyway, what I care about more now is: check gas/slippage before trading, set limit prices when possible, don't misuse RPC, and don't fail on signatures again (that makes me angrier than losing money).
Ridiculous, truly ridiculous.