don't forget there are different torque settings for lubed bolts and dry, if you copperslip or similar a bolt that has a dry (non lubricated)torque setting and tighten to the dry setting, you have possibly over tightened it,
before anyone says they have never had a problem,you might not have, but you have been lucky, its bad practice...
have a look on google and see what can happen, especially on smaller bolts,
i,m a mechanical fitter at a power station , and also run a bike mot business, i see overtightened stretched/snapped bolts all the time,usually down to this problem...a bolt too tight can snap, stretch beyond its elasticity limit and loosen/snap,or it can just strip the threads , whatever, not good........
if you must lube a dry bolt and torque up, accepted practice at work is torque to 75%, but that isn't exact, so don't quote me....
another point to note is a setting for say, an 8mm bolt will not be the setting for a similar looking bolt elsewhere, base metal, thread type, heat (expansion/contraction), and different bolt material all play a part, so double check, don't just think its the same as the last bolt,
sorry if I'm teaching folk to "suck eggs" here, but some genuinely don't realise, (if they did i wouldn't have so many stud extractor's, lol)