Now the rockers are back together to play Glasgow tonight, and the band's Scots-born bassist Frankie Poullain reckons a key part of their reunion was realising they could laugh at each other again.
"We got over ourselves, and realised we're all idiots," said Frankie, the first member to leave the band, back in 2005.
"I suppose as you get older you take things less seriously, and all the best things in life happen when you lose your ego. The four of us just take the mick out of each other."
It wasn't fun near the end of The Darkness the first time round, though. Their rise was phenomenal, with their brilliantly catchy tunes, spectacular stage shows and tongue-in-cheek humour making debut record Permission To Land a huge hit, going five times platinum, and leading the band to play the likes of the SECC.
They even won three BRIT Awards, but everything went rapidly downhill after that. Frankie left during recording sessions for second album One Way Ticket To Hell - And Back, the album itself underachieved and the rest of the band soon fell out, too.
That meant singer Justin Hawkins checked into rehab, and then formed his group, Hot Leg, while the others played on as Stone Gods. Frankie, however, remained out of music, and travelled around the world instead.
"Most of the music offers I got were for clichéd classic rock type things," he explained.
"I thought The Darkness was never traditional heritage rock, it was always done with a twist, which draws me to it."
The offer to rejoin The Darkness, however, was too tempting to turn down. After brothers Justin and Dan Hawkins patched up their differences, a Darkness comeback was always on the cards.
"I don't know what the hell happened, I guess that the same sparks that draw you together can also work the other way," he said, loking back at their break-up.
"We were quite a volatile combination. I think it was quite good to be away for six years.
"Now we have recharged our batteries and are back feeling fresh."
As they're the rockers who once featured Justin riding over the crowd on a white tiger stage prop, and the same guys who decided to release a cheeky Christmas single, the return of The Darkness was done in typical fashion - before thousands of fans at the Download festival earlier this year.
"At Download there was a lot of pressure, and to be honest we were amazed there weren't any bottles thrown at us," said Frankie.
"We were amazed - there were all these young guys cheering, who must have been 10,11, 12 when they first heard us. I guess that makes sense, as that's the age when you get into your first band, and they'd never seen us. It was really exciting."
Now they're back on the road, not quite playing arenas again but still gigging in the decent-sized likes of the O2 Academy. A selection of new material is also promised for tonight's gig.
Frankie said: "Some of the new songs sound bigger than before. The guitar playing has never been better and a couple of tracks had an Abba-esque tone, that 70s symphonic pop-rock style, so there are songs like that.
"Then there are all-out rockers. The main thing is that the songs are coming from a good place, they're warm-hearted."
Frankie said of X Factor contestant Johnny Robinson, who tackled the band's anthem, I Believe In A Thing Called Love: "He was trying to overcome his limitations, and he put his heart and soul into it, which was pretty brave.
"I'm not a fan of the show but he put himself on the line. I think that's a good thing, there's always a place for outsiders in music. I would say we're freaks - and you have to be in touch with your freakish side in music."
lThe Darkness, O2 Academy, tonight, £25, 7pm.