Well, I remember one I worked on ...
We finally managed to get head office approval to buy it. It had taken a long time. A very long time, and then we placed the order. This was delayed by the question, "Well, what color do you want it?". We had no idea there was a choice. We wasted three weeks deciding that black would fine!
After it was installed we started having loads of problems. It would crash, and the dump was always corrupted (yes, we used to get and read AND UNDERSTAND!) core dumps. The Cray engineer was baffled. His home support was baffled. The designers were baffled. Eventually we traced the times when it got trashed to when a certain female operator was on shift. She would walk past the machine and lovingly touch the side - only to earth the static from her nylon underware in to the machine. We had to ask that females kept away from the machine. The union went mad and complained that this was blatant sexist discrimination and that they would ballot for strike action. I just wish I had been in the meeting when the head of the data centre explained to the union rep what the problem was, and that the alternative was to have the duty sysop check that all the females were wearing silk or cotton underware! No, before anyone gets at me I am seriously not making this up, but I will protect the site from embarrasment!!!
I also remember being the client lead trying to hook a VAX 11 up to the Cray so we could load jobs and get back results fast. Up until then we had a serial line to a an IBM Mainframe, but the Vax was going to be Massbus connected. Imagine, as far as the Vax was concerned, the Cray was just a peripheral. On the big day when we wired everying up, it all went horribly wrong. As soon as the Vax tried to access the Cray, the Cray powered down. I had to wait until 2am to get a Cray senior engineer on site. I was well impressed when he had me connect a pulse oscilloscope on to the Massbus and we watched the signals going down the line. After 2 hours he took the back panels of the VAX and showed me where two pins on the backplane were a little bit bent and touched from time to time. Not enough to crash the VAX but enough to crash the Cray. Fixed with a gentle tweak by a pair of pliers and never a problem since then.
Overall I worked on Cray-1 and Cray-XMP. One of the other sites had a Cray-2 but I only saw it, never go access to it. We were talking about a Y-MP when I left the company. Ahh those were the days, when a super computer looked like a real super computer.