I'm just after deleting a comment again.. It was a nice comment to my car related entry, the language was correct, etc.. But the real motivation of leaving the comment, was in the end of it - a link to a car dealers.
I don't mind people posting links in comments, if those links go to their personal pages or blogs, or if someone wants to contribute a useful link that's related to the topic I've blogged about. However, when someone pretends to be interested in my blog entry, only to leave a business link, which is in no way relevant to me (=I already bought a car, and even if I was looking for one, I wouldn't buy it from the US.), I find that lame, and I'll delete their comment, no matter how nice it may be.