Why do people insist on being such bums?

[Rhyfelwyr]

Well, often people who don't stick with formal customs are not nice people. So I don't know what kind of general conclusion you can make, other than "insincerity is bad". But tact isn't insincerity. If you don't like someones painting for example, insincerity is praising it, tact is not making them feel bad just because you don't like their painting, which can involve giving an honest assessment.

"insincerity is bad" is precisely the point I was making. Of course, not all people that do not bother with formal customs are nice people. I have no idea what percentage of people that bother with such customs are nice when compared with those who don't, there would probably be too many indirectly related factors to get a meaningful statistic.

Also, tact is a whole different matter from formal customs. There can be overlap but it doesn't have to be so.

If you don't respect them, isn't it honest to be disrespectful? :p

Yes. I think everyone is afforded some level of respect as human beings, but beyond that I'm not going to pretend. At least be disrespectful in an open way.