how come people are so often insensetive....

People are insensitive, as they don't care about others or their problems. A lot in this world believe, that only they exist and only they have the right to treat others as insensitive as they want. TATA.

People are insensitive cuz they just overlook at certain events. They have no idea that something is happening or they're doing something inappropriate and they'll only know it if you inform them. It's not really their fault most of the time.

I think people are that way because they are too ignorant to know better, and also, because they lack self confidence, and feel that the best way to even things out is to bring others down to their level, instead of improving themselves, and rising to the level of the people that they put down.

People, most of them are selfish and that is what which makes them insensitive to other people.

People learn to be selfish by copying the selfish behaviour they see around them. Children can be self-centred but that is a survival mechanism, good parenting soon stops that kind of behaviour. If their parents are self-centred then the children will be as well. As you said, this means they become insensitive to the needs of those around them. some of them are simply unaware that other people have feelings and needs but some, very definitely, are aware but CHOOSE to be selfish because that is what they are used to and have convinced themselves is the only way. They think everyone they meet is going to be as selfish as they are which is a very sad way to live their lives.

a bad day perhaps. there is just little chance of living up to expectations by others. the better the day, the calmer the person and it's not even enough. people are not perfect after all.

I think you can't please all people of being insensitive. You can do something to cool of their head. Give some icecream and melon flavor drinks. Make some joke to ease issues.