My beef with diesels are smog and age.
Year after year it's the same old claim of clean diesel cars.
I'm not saying there isn't improvements as they have made great strides.

But 95% of the time when I see an older diesel it either smokes or doesn't smoke but is blowing that unique toxic gas that stings your nose and burns your eyes and throat shut.

Yes these cars were clean by the standard of thier day but now their older- I've noticed usually after 7 years the deterioration begins.
Yes there are older diesels that are fine but these are the exception not the rule.
Yes older gasoline cars can also smoke but the toxic gas described above is absent.
Yes diesel drivers love their car and that's fine- but I avoid like the plague not to be behind one. If I'm stuck in that situation I double my traffic buffer to let the gas blow off to the side.

It will be 14-20 years before I ever consider buying one. In my case it will take that long for the usual yearly claims to prove as reality.