We are taught cum preached to care for other's feelings and emotions. We must exercise certain deeds hailed in holy texts.
Why such things matters when we all will die one day?
Even animals care for their young ones (their feelings and emotions also). This is an already-installed quality in most living things. Haven't you seen mother birds hatching their eggs? Will they hatch if no care is given? ...Bees caring their larvae? Are they all necessary to maintain the equilibrium of nature?
What would happen if no care (for feelings and emotions) is given to the disabled and the aged?
Think about the development of your language and your favorite pieces of music. If no care was given would they develop as you use or enjoy them now?
After reading the following, please don't blame me.
If nobody cared for you, your parents would leave you as a waste within a few hours of your birth. And you wouldn't get any food even for the first few days. Your mother also wouldn't get any care from others. I don't need to explain further. Here I linked 3 persons only. You may make this chain longer. Considering others also you may make or think of a web.
I don't need to explain your character (if you survived) if your parents and grandparents didn't get love and care from anywhere. I leave it for your thought. You will understand how civilizations develop.
We must exercise certain deeds hailed in holy texts.
This is not necessary everywhere (or in all categories). Try to read other holy texts also.
Man is a social being. He can't grow or develop without others' help.
From your question I guess you are asking about man as a being neutral in character (Whose deeds cannot be considered as good or bad).
(Although most often it is relative,) There are people having good and bad characters. You can live in this world without doing anything good. But you should be ready to accept its consequences without any complaints. And before saying "Yes", you should know one thing -- Every thing you are tasting/enjoying now is because other people and animals are maintaining love and care for others' feelings and emotions and also because they are doing good. Otherwise you would be living as member of an uncivilized primitive tribe. [I think even those primitive men care for their progenies' some feelings and emotions.]
Humans have developed brain and many things they experience will make impressions in their mind for a long time. Normally, he feels attachment towards things, places, people etc and becomes stronger as time passes by. You begin to say "these are my things, my people" etc. And their wishes, feelings etc are more varied than other animals'. As you know humans can control their feelings as well. Also, they have some special feelings like pride, shyness etc. They wish to be loved and cared by others. Since they can think better they always try to do and enjoy everything in a better way. The best way to fulfill their wishes, feelings etc is to be good and do good to others. And then only their mind will be free from worries. They know that.
Please understand this:
You may live in the society without any good character; without doing anything good. You feel problem only when you begin to ask some questions to yourself. (This happens especially in one's old age.)
E.g. I have enjoyed my life with the help of others. Did I do anything good for them in return?
Who am I really? What is the aim of human life?
I am born with many abilities and interests. Did I have a past life? If so will I have a posthumous life?
Where will I go after death?
Will I become a mere nothingness after death?
I wish to enjoy this world again. Will I be born here or somewhere else?
If these types of questions don't worry you, and if you don't do anything bad to others, there is no problem to them (i.e., to others).
But the final authority to decide whether there is any problem to you, is none other than you.
Mind is everything. It controls your whole life. Upon it depends your happiness or misery, success or failure. "Mana eva Manushyanam Karanam Bandhamokshayoh" thus say the Upanishads. Again, 'Yena Manojitam Jagat Jitam Tena' is the great truth. As you think, so you become. Do you fully realise now the great importance of controlling, training and overcoming the mind? So long you have neglected the care of the mind. Attend to this vital subject from now. Mastery of mind means success in all fields of life. To achieve this mastery you must study the mind. You must understand its nature, habits, tricks and the effective methods of bringing it under restraint.
To read the full text see: http://sivanandaonline.org/public_html/?cmd=displaysection§ion_id=476
If you wish to know the differences between man and animals, please read this:
If you found the things I mentioned above logical, (You may ignore the religious texts mentioned here) you may take it as base and try to understand holy texts. And you will certainly understand whether they are useful or not.
To do good implies to be good. To know more about its ultimate importance, please read the following extract from a website:
Satsangatve Nissangatvam Nissangatve Nirmohatvam Nirmohatve
Nischalatattvam Nischalatattve Jeevanmuktih ... Bhaja Gonvidan, Bhaja Govindam
Meaning: Sat sangatve - through the company of the good, Nissangatvam - (there arises) non-attachment, Nissangatve - through non-attachment, Nirmohatvam - (there arises) freedom from delusion, Nirmohatve - through the freedom from delusion, Nischala - Immutable, Tattvam - Reality, Nischalatattve - through the Immutable Reality, Jeevanmuktih - (comes) the state of 'liberated-in-life'.
Substance: The company of the good weans one away from false attachments; from non-attachment comes freedom from delusion, when the delusion ends, the mind becomes unwavering and steady and from an unwavering and steady mind comes Jeevat Mukti (liberation even in this life).
It is indeed a biological imperative to survive and also to procreate, as SonOfThought mentioned, so our biology gives us meaning, but it is a complicated question.
Your question is a fundamental question of nihilism. Answers are going to be a bit subjective. But in that subjectivity we can find an objective response: you can find your own meaning in life. Our lives can provide us with a level of subjective satisfaction, and that allows us to find meaning, even if the universe itself provides none.
We should care because after we all die, after the heat-death of the Earth when the sun expands, the only thing left from our entire lives will be the other persons with whom we interacted.
Jesus said, "I tell you, use worldly wealth to gain friends for yourselves, so that when it is gone, you will be welcomed into eternal dwellings." (Luke 16:9)
Turn the question around. What do you gain by not caring? If the holy texts are done with, and you wish to go beyond animalistic instincts, then in your new freedom you must use your mind to decide how to be.
Being selfish, greedy, violent, and in prison, probably aren't great ways to start, so better work out where you do want to get to. It neither matters, nor not matters. Mattering or it's absence are just props. Choose your props wisely.