Thankfully we have lots of other options than Starbucks. Yeah, burnt from over-roasting. We tend to the other options when we're out, fresh ground French Roast at home. But Starbucks is like hitting a fruity juice with too much power! Definitely burned!
Comparing brewing devices, grinders and beans to vaping.... hardware and expendables... Actually, I think I spend more on coffee now!
Nic and PG seem to be the big "drivers" of TH. Which, to me, isn't a harsh taste, more of a hard taste. Hard to describe. But the way I see it, harsh is more like burnt - or dry - hits. So if you really like that juice, maybe try a different PG/VG ratio?