Strange "far out" orbitals in HF and DFT calculations. Why do they occur?
As already mentioned in the comments you have to be careful when interpreting the meaning of the virtual orbitals in a ab-initio or DFT calculation. In the calculation the only orbitals that are optimized are the occupied orbitals while the virtual (unoccupied) orbitals give you a guess of the shape you expect from them if they were occupied. To look at it from a simple perspective, somehow you are using the LCAO method, you obtain as many MO as AO you are using in your basis set, but you only optimize the MO that are occupied.

There is a second point that may be relevant to your question. In many programs the default orbitals you get in your calculation are the canonical orbitals (delocalized orbitals) that even if occupied may not have an evident chemical interpretation on its own. For those porpouses it may be better to use localized orbitals (e.g. NBO) that may be easier to interpret.

Two book recommendations:


C. J. Cramer, Essentials of Computational Chemistry. Theories and
Models, Wiley (2004). 
Frank Weinhold, Clark R. LandisDiscovering chemistry with natural
bond orbitals, Wiley, 2012