My deepest apologies.

It is my understanding that my invading forces, in their attempts to besiege your cities and snuff out all life on Azeroth, have inconvenienced the activities of common civilians. In the future, I will ensure that your commanding officers are informed well in advance of planned invasion times so that they may properly fortify themselves.

I have also looked into the issue of my plague being too quick in its purpose and too difficult to cure. Please be reassured that I have taken the matter up personally with my top necromancers and that any further incarnations of said plague should be only a slight challenge for your natural immune systems to overcome. Please forward any additional complaints to either Kel’thuzad or Anub’arak. 

Regards,
the Lich King Arthas.

(Source)