Sunnah regarding hospitality to guests
Muhammad Abd-al Mannan

O Allāh Almighty! Bless our Lord and Master Sayyidunā Muhammad [may Allāh Almighty bless him and grant him peace] as many times as there are created beings.
Looking after your guests gains you much barakah and reward. Not only will it please the guest but you will also gain satisfaction from amal also. There is no better example for this amal except in the life of the beloved Messenger of Allāh [may Allāh Almighty bless him and grant him peace].

It is up to you to eat
Jabir [may Allāh Almighty be pleased with him] narrates from the Messenger of Allāh [may Allāh Almighty bless him and grant him peace] that, Whoever is invited to a meal accept it, whether you desire to eat or not is your choice. [Imām Muslim's, Sahih]
If you are not hungry it does not mean you don't attend, but it will please the host if you at least attend but are you are not obliged to eat.

Respect your guest
Abu Hurayrah [may Allāh Almighty be pleased with him] narrates from the Messenger of Allāh [may Allāh Almighty bless him and grant him peace], Whosoever believes in Allah, The Exalted, and the day of resurrection should respect his guest. [Imām Nawawī's, Riyādh us Salihīn]
To look after also means to respect them and make sure they are happy and making sure you fulfil their needs.

Look after your guest
Abu Lahoos Jismi [may Allāh Almighty be pleased with him] narrates from his father, he says, 'I asked the beloved Messenger of Allah [may Allāh Almighty bless him and grant him peace] I went to a person's house [as a guest] and he did not look after me, he has now come to my house, shall I look after him or treat him as he treated me?' The beloved Messenger of Allah [may Allāh Almighty bless him and grant him peace] replied, Look after him.
This is the beautiful and blessed character of Allah's Beloved Messenger [may Allāh Almighty bless him and grant him peace], may Allāh Almighty give us a drop of the character of his beloved, Ameen! 

See the guest to the door
Abu Hurayrah [may Allāh Almighty be pleased with him] narrates from the Messenger of Allah [may Allāh Almighty bless him and grant him peace] that, The Sunnah is this, that you see your guest to the door. [Reported by Ibn Majah]
Abu Hurayrah [may Allāh Almighty be pleased with him] has related that the Messenger of Allah [may Allāh Almighty bless him and grant him peace] said, One should welcome his guest by coming out of his door and while bidding farewell should accompany him to the door of the house. [Reported by al-Bayhaqī and Ibn Majah]

You will not be called to account
Jafar bin Muhammad Sādiq [may Allāh Almighty be pleased with him] states that, When you eat with your brothers and friends on a floor mat, do not rush as this is the time that will not be accounted for.
Hasan Basrī [may Allāh Almighty be pleased with him] states that, Whatever a person eats and drinks and feeds his mother and father, will be accounted for, except for food eaten with friends.
Glory be to Almighty Allāh! We learn that to have food with friends is a greatly rewarded act and love will increase between the Muslim communities.
'Ali [may Allāh Almighty be pleased with him] states that, To put food in front of brothers, to me is better than to set a slave free.
In a blessed hadîth it has been stated that there three times when one will not account for his deeds in front of Allāh Almighty the first is he who makes sehrī [meal consumed early in the morning by Muslims before fasting], the second he who makes iftār and third the one who eats with friends.