I'm trying to replace my kitchen faucet's aerator, but as I'm tightening it, it'll reach a point where it sort of "pops" and becomes loose, allowing me to tighten it again. I'm not sure if that's a bad sign.
Anyway, I thought it might be due to all the grime that's built up on the faucet threads, so I took a toothbrush and some oil and scrubbed it down pretty well.
Unfortunately, that didn't work. Taking the O-Ring out does allow me to tighten it completely, but that has a side-effect of causing the water pressure to be absolutely ridiculous.