One of Bruce Charlton’s defining essays.  A must read.  Agree or disagree, you ought to grapple with it.

Jesus was, of course – overall – a nasty person. He had his nice moments; but for the nice people he would certainly have seemed nasty. Jesus was, indeed, loathed and feared by the nice people of his era; because he upset and insulted people; he made others unhappy, miserable and afraid; he gratuitously stirred-up trouble of many kinds.

And Jesus had that defining nasty quality of not being bothered what other people thought of him.

The terrible, nowadays fatal, weakness of nice people is that they need to be regarded as nice by other people; their self-image is an internalisation of other people. Niceness is a deep conformity.

–thus Bruce Charlton (italics my own)

And thus offense becomes weaponized and courtesy becomes the ring in the nose.

Niceness is a set of principles for getting along, for smooth social interaction.  Whether it is a virtue or not depends on who, or what, you are getting along with.

The word history is interesting.  In early modern times and into the 19th Century, nice meant something like ‘discriminating, fastidious.’  A person who wasn’t nice would be a person who wasn’t very particular in their choice of companions.

In his life, Jesus was kind.  Jesus was loving.  To the point of being terrible.  The episode with the rich young man is one where Jesus’ love is apparent–but not a bit of being nice.

Though I see a danger in directly aspiring to Not Being Nice.  That would be missing the forest for the trees.  One of the techniques of modernity is to manipulate certain principles in a way that makes them loathsome–a natural reaction is to embrace the opposite of the manipulated principle as your goal–but usually  the opposite is a bad place to be also.  There is almost always an excluded third goal which should really be embraced.