Reason five has got to be the best one.

However, you have to remember a few basic things, like the fact that being nice can be a waste of time (I love the fact that this community doesn't entertain "thank you" and "good job" as comments on their own), and that not everyone's definition of nice is the same. Monosyllables really -are- confusing when too much goes non-unpacked (un-unpacked? disunpacked?) inside.

Finally, re the aside on spelling, if there were an automatic "niceness checker" available the situation might be different, but as things stand poor spelling is a signal for laziness.