I flew BOS-LHR and return last year in Y. On the outbound my IFE wasn't working (just mine). The crew was very apologetic and tried re-setting it a couple of times to no avail. They gave me a form to fill in (from which I subsequently got a £25 voucher) and also made a bit of a fuss of me for the rest of the flight, plying me with red wine which basically made me sleep the rest of the way!

I couldn't believe it, but on the return journey I had the exact same problem! I told the crew that this had happened on the outward too. Again they were apologetic. Y was full, but they moved Mrs User Name and I into WT+ for the journey.