Why can Type O Blood be used by anyone in the world?

Blood group O (or blood group zero in some countries) individuals do not have either A or B antigens on the surface of their RBC, but their blood serum contains IgM anti-A antibodies and anti-B antibodies against the A and B blood group antigens. Therefore, a group O individual can receive blood only from a group O individual, but can donate blood to individuals of any ABO blood group (i.e. A, B, O or AB). If anyone needs a blood transfusion in an extremely dire emergency, and if the time taken to process the recipient