Favoritism is common here ever there is a presence of Human. It is not only natural tendency of human being but also one of the psychological requirement processes which makes a an individual get influenced by something which soothes him. And it is like a spring how much you suppress such behaviors that much of chance you will have of it bouncing back.
Coming to the issue of inequality, this need a keen observation. Because just because one appreciate another infront of you, it is obvious you feel low and sometimes emotionally attacked because of it. This does not mean you are not treated equally. Id you are deprived only of the attention of your HR towards you then it is not something called inequality.
Coming to unfair treatment, this is major concern of almost all the employees when it comes to HR and employee relationship. The reasons are many for this, reasons like HR being tempered, who fails to draw the line between his personal and professional relationships, lack of abilities, complexities within himself against certain employees, or regarding knowledge and skill sets, over lenient towards employee, rigidity, over flexibility and volatile, pressure from superior as such..... And these only as individual one shall improve and hardly others may assist him towards development.
Bias, is again a detrimental issue at workplaces. This happens more when you have well know people at work places, when you are more open to appreciation and less or nil towards criticisms, lack of patience and ability to differentiate on a valuable parameters, interest in self portraits, easily provocable mentality, easily being influenced, superior issues, pride and prejudice..........
In lemine, it all looks very easy and bold but they are very subtle and disturbing issues to be taken care by the HRD department. And the employees do suffer because of these no doubt. Many of the times HR will even wont be aware of these matter that employee are suffering or having issues.
So, knowledge of the same is very important, hence one must always inform in an acceptable impersonal manner to the HR whenever you get the chance to have a talks. Do not do the mistake of telling it on the face like hitting a ball with full force, also avoid it during the meeting unless asked fro, because certain Hr take it positives many take it negatively and this leads to the added issues.
If you do not feel like talking to your HR alone then you may write an anonymous latter and leave it his desk, or it may also be signed by many or supported by your colleagues.
Always fix a suggestion box in your department addressing to the employee requesting to resolve the issues and kindly do nit misuse the same for personal grudge and for playing pranks.....
One good thing to do would to talk to hat employee who is a friend of the Hr and know more about their relationship strength and try to use that employee as mean to reach the end by utilizing them, since Hr would be a kind of binding because of unsaid reasons towards his friend and you get what you want through him......
And most importantly, as I have explained it above, try to analyse the matters thoroughly keep aside your emotions you will surely feel better and get the ideas to dig the path......
If none of these works out and HR is beyond repair. directly approach the superior and request for the change of HR as soon as possible......but what ever you do be united and strong.......
(I personally regret why HR fails to understand what is going on around him and try to correct it with positive and professional attitude...... )
Wish good luck....... have a nice day,............