[bobandbill]

As said it depends. If it's flaming I would ignore it, or maybe laugh to myself about it (and I guess one can't please everyone anyway!). If not then I'd read it, think how they must be totally wrong, go take a walk, and read it again and then probably accept they may have some points, although that depends how they back up their criticism. =p If it isn't I think I would probably reply with a 'please explain'.

Constructive crit of course is a different matter.