The only problem that I had was due to the poor quality/printing of the instructions. Although assembly of the major components seemed obvious I decided to FTFM. Had to keep looking a couple of pages forward to find out what not to use. There were several parts of the same length and similar aspect ratio - although of differing cross section - but the sketches were too poor to be certain which was which without eliminating some.
I once assembled a "tall larder unit" (not from Ikea). Looked at the leaflet, discarded it after checking that all components were present, built the thing with no problem, then had to fit a not-too-obvious tie-bar across it so that the shelves would stay in place!