And when you are greeted with a greeting, greet [in return] with one better than it or [at least] return it [in a like manner]. Indeed, Allah is ever, over all things, an Accountant. [Qur’an 4:86]
Allah gave us a better greeting than “good evening”, “hi” and so on: the salam, which carries a supplication of peace and it is the greeting of the angels the the people of Jannah. Greeting each other with non-Islamic greetings should be avoided as well as the habit of hugging and kissing which should only be reserved to meeting a person after a long absence, such as one who just came back from travel.
Anas Bin Malik reported that a man asked the Prophet, “O Messenger of Allah! When one of us meets his (Muslim) brother, should he bow his head to him?” He replied, “No!” The man asked, “Should he embrace and kiss him?” He replied, “No!” The man then asked, “Should he shake his hand?” The Prophet replied, “Yes!” [Recorded by at-Tirmithi. Verified to be hasan by al-Albani (Riyad us-Salihin no. 893)]
There is a great reward for a man or woman shaking hands with a Muslim brother, respectively with a Muslim sister as Al-Bara’ Bin ‘Azib reported that Allah’s Messenger said:
Never would two Muslims meet and shake hands but they are forgiven before they separate. [Recorded by Abu Dawud, at-Tirmithi, and others. Verified to be authentic by al-Albani (as-Sahihah no. 525)]