I am sorry for all the people having problems, but my Prusa mjni is finally just workjng and happily printing all the stuff I throw at it. Its been having issues here and there forever. I just figured out that the hotend has not been assembled correctly (heatbreaker to nozzle seal was weak) which became a greater issue when switching to a 0.25mm nozzle. Now after I fixed it, it is just awesome :)
I printed a large complex part once, only to see I overlooked another thing that got in the way of my part. Instead of changing my design and re-printing it (which would take hours), I walked over to the mill and milled off a section of my print so it would fit properly. Plopped it on, fits like a glove, design king status achieved!