I did a bit of delving into their OS & (eugh) accounting/stock-control software back in the 80s when their programmer swore blind that the errors were due to us and not him. Even after I put a finger on his fuck-up he refused to accept that his program would ever execute that bit of code - kinda curious since he wrote it. Also kinda curious in that when I put a breakpoint on it, it stopped there. Trumpishly, he wouldn't accept that I hadn't made his crap pass that way.
Brass rags all round and Wera didn't offer me any freebies. Not even lunch, never mind tools. Wera Paris, that was.