Whenever I see the deities of God (in temple, TV etc.), hear spiritual discourses or chant the Maha Mantra, tears run down my eyes. Why does this happen and what should I do?

Everyone in this world is unique by virtue of his/her mental faculties and emotional quotients. Some people are more emotional than others. In such a scenario, these incidents arise when you hear about / see the deities. However you should ignore them by not attaching much value to them and continue to chant the Maha Mantra. In due course of time, you will be just fine.

I am reading Bhagavat Gita and trying to follow what it says. Initially it seemed easy but it is not so anymore. I am losing my concentration. Secondly, I am short tempered and I want to change instantly. But as the change is gradual, I get frustrated at times. Please suggest ways to improve my concentration and the way I think about others.

The actual essence of Bhagavat Gita is surrender. – Surrender unto the Lord and be a mere instrument in His hands – that is what Bhagavat Gita conveys to us.
The easiest way to surrender is to chant the Mahamantra. Continuously chant the Mahamantra and eventually, you will attain the state of surrender. You will also see that while you chant the Mahamantra, you will slowly get rid of your negative qualities like short temper and your concentration, optimistic attitude and positive mentality will improve.

I have read in one of your messages that we should not be susceptible to emotional injuries that others might inflict upon us or emotional influence that others might try to wield on us. How to grow into such a state?

Try to see Krishna in them and in everybody. Accept all the happenings around you as His divine plays. Put yourself in the other person’s shoes and think how you would act. Act with wisdom/discrimination (‘viveka’) always. Whenever you are emotional, refrain from taking any critical decisions. Allow yourself to calm down before taking any decision. Whenever you take decisions, ensure that the decision is driven by the brain and not by the heart. If the later comes into play, it ends up in a mess. Control your emotions through asanas and simple breathing exercises. Be cheerful always and always remember that the sky is your limit. Small incidents in your day to day life should not affect your cheerfulness.

How can I help others and yet not get unduly attached? I wish to help and serve but sometimes get involved emotionally.

When ever you are helping someone, remind yourself that Krishna is only helping them and that you are only an instrument and nothing more. Pray to Krishna that you should not be affected by the outcome of the help.