In studies of viruses, lectins and especially human blood anti-glycan antibodies using printed glycan array (PGA), sulfated glycans suspiciously often turn out to be the highest-level binders. The binding to sulfated glycan along with parent neutral is easily explained by the similarity of these two glycans, while the unexpected thing is the many times stronger binding. Analysis of data accumulated over almost two decades allows us to explain the observed effect by the Coulomb interaction of the sulfate residue with a positively charged amino acid that accidently appears near the binding site of the neutral glycan backbone. That is, there is an effect of enhancing the specific interaction by an additional electrostatic one. It is expected that the material considered in the article will be useful for the correct interpretation of other data on the specificity of proteins capable of binding charged glycans, which are often encountered in nature.