The primary causes of thread damage are installer error or impatience—often both. Starting a bolt or screw out of alignment is the most common, and it’s easy to do when the hole it threads into is hard to see. Fastener alignment is especially tricky with those that pass through several components like body panels that all need to be aligned before you can even see the hole behind them. Juggling all those pieces while trying to get the threads to mesh is where the trouble usually starts. The bolt goes in, makes it half a turn, maybe a whole one, and then you feel resistance. When this happens the urge is to bear down on the wrench or get a longer one, which only makes it easier to strip the threads. Stop right there.