I don't like when people rev cold engines. And yes, this includes Piero Laverda doing it...
I cut friendship (not only, but also) due to a person doing this to a bike I owned, although I asked him not to do it and he agreed not to do it. The Moment he turned on the next street, 30 meters away from me, he pulled WOT in every gear. When he returned, I did not say anything, I just took the keys off the bike, parkt it, turned around and went inside. I never spoke with him again.
It was just the last drop that made the barrel overflow for me. It was showing his ignorance and missing respect for my property and - much worse - for me and our relationship.
It just does not feel right to rev a cold engine. They do it for show while it just makes people shake their heads, thinking "what an idiot".
roughly 42 years ago, I was on Michael Schumacher's fathers Go-Cart track, when a guy showed up with a chrome framed cart with 3 (!!) hydraulic brakes, sequentaly shifted 250ccm Yamaha RD 350 LC 2-cylinder 2-stroke engine, spoilers and instruments on the thing etc. It looked a bit like a Formula 1 car in sun-yellow.
They kick-started the engine and he rolled on the track, when a very quick cart (potentially Michael before he got famous?!? Driving style had loads of similarities, but I can not proof it) turned around the 180° curve where In and Out of the track is. He slowed down, looked at the guy and gestured he should push throttle. The "formula-1-alike" Cart driver looked at the instruments and showed him "no-no", as water temperature wasn't where it should be I guess.
It took 2 or 3 rounds and they came along again at the same place, the quick driver showing again "come on, let's push it". The Formula1-alike cart driver looked again at the instruments, pulled clutch, shifted down 2 or 3 times and what then came, was out of this world... "paaaah, paaaah, paaah, paaah - pah, pa, pah Paaaaaaaah, paaah, paa" - you could hear him shifting and accelerating, breaking etc. along the whole track! The fast rider tried to follow - no f*cking chance!.
I spoke later to the "formula-1" driver. At this time, there was no class for such carts to race them in, at leat not with 350ccm engines afaik. I asked him what this is for then: "For fun. I make them for friends, with 250 and 350 engines. The 350 is tuned for close to 70HP." on a cart that weights less than 100kg... no wonder, he needed the spoilers and the rear wing... I found it very smart he didn't get tempted to show-off and waited until the engine was warm enough.