Confused, how to determine a good deed?

Bismillah hir Rahman Nir Raheem

My Lord, expand for me my chest [with assurance] And ease for me my task And untie the knot from my tongue That they may understand my speech. Ameen

I used to hear stories of one of our relatives he used to say that 'I like a particular act of hindus that when they greet their elders they bow down and touch their feet to show their respect', my father used to say to us that who declares what is a good deed? who sets the standard of a good deed? A common Muslim would say that of course it's not a good deed. I ask why? a common answer would be because hindu's do that, is that the standard? I read a comment on facebook of a Muslim brother saying that I love how in Ertugrul series whenever the name Prophet SAW comes they, to show respect, put their hands on their chest

 and one of the brother said we respect our Prophet SAW by kissing the fingers (I don't mean to target a sect but the deed itself). Now what would a common Muslim say about these deeds? He would probably say that it's okay they are showing their respect for the Prophet SAW, again on what standards did they measure it was a good deed or not. Do Islam tells us to do anything we like, what our hearts desire, what we think is right?, what our ancestors used to do or what our sect's imam or maulvi has said? Do that constitutes Islam or is it something else because if it did then what was the need of sending Prophets in different communities.

Let's keep it short, the standard of a good deed, how to know if this deed is good or not? The first question that arises is, what is the purpose behind the deed? or for what purpose is that deed done? Is it to please Allah or someone else? If it is to please Allah then the second question that arises is, The deed, good in the eyes of who? because something might be good according to one person and bad according to other. If the deed is to please Allah then it should be considered good by Him, right?! He should tell us what pleases Him and what angers Him but He won't talk to us, now how are we to find which deeds pleases Allah, for that he chooses bests of men from amongst us and tells them what He likes and dislikes. Who are these men? Sufis?!, Darwaish?!, Walis?! He chooses the Prophet and convey his likings and disliking through them and Prophet Muhammad SAW was the last Prophet. He was the last person to convey us the message of Allah, of his liking and disliking and that was final. No person after him can tell us that this deed is good, that deed might be good in the eyes of this person, but if our Prophet didn't tell us then it's not good no matter how pious the person whose telling the deed is and it won't please Allah. Some people give an argument that Prophet didn't told us every teeny tiny thing, I am like who the hell are you to say that about the Prophet just imagine, the Prophet who even told us how to cleanse ourselves what else would he hide?! and Allah says in Quran

Messenger, preach what is revealed to you from your Lord. If you will not preach, it would be as though you have not conveyed My message...

[Al Maida 5:67]

Now comes the other part how to verify in these times that the deed is good or bad or one could use the term 'Amal Salih'. There are two conditions for an Amal to be Salih or for a deed to be good and acceptable in the eyes of Allah and both these conditions should be fulfilled.

1) Intention, purely for Allah: 

Narrated 'Umar bin Al-Khattab:

I heard Allah's Messenger (ﷺ) saying, "The reward of deeds depends upon the intentions and every person will get the reward according to what he has intended. So whoever emigrated for worldly benefits or for a woman to marry, his emigration was for what he emigrated for."

Sahih Bukhari Hadith no 1

The deed, one is doing should be purely to please Allah. It should not be because all the neighbours are doing it so we thought we should do it, or our teachers said so to please them we have to do that. Recently we had a graduation ceremony and in it they were telling us that when the registrar announces your school you should stand up and when they declare your degrees everyone should bow down and say I do... I was like why bow down they were saying it's a tradition of the ceremony I was like the hell with the tradition a Muslim only bow down in front of Allah not to any one else ( I didn't said that but that's what I thought). 

2) The procedure of that deed should be according to the procedure of Prophet SAW:

Why did I use the word procedure? because in procedure you have to follow every single step for that procedure to be valid. In the same way you have to do the deed exactly the way our Prophet SAW did not to add your mirch masala. In Surah Al Hadid Allah mentions followers of Hazrat Isa AS

... and We sent Isa son of Marium afterwards, and We gave him the Injeel, and We put in the hearts of those who followed him kindness and mercy; and (as for) monkery, they innovated it-- only to seek Allah's pleasure. We did not prescribe it to them, but they did not observe it with its due observance; so We gave to those of them who believed their reward, and most of them are transgressors.

[Al Hadid 57:27]

Allah says that their intention was purely to please me but the deed they invented was not prescribed to them by their Prophet. So the dialogue some people use that intentions should be pure no matter the deed👆...

People might say nothing happens in reality. I agree nothing happens in reality that's what's scary? you are doing a deed your whole life and in the end Allah asks you who told you to do this deed? you came to know that this deed is not according to the teachings of Prophet. If it happens in this life then what comes after it is important either you stop doing the deed or continue doing it but one should remember that Allah don't punish on things done in ignorance BUT it is our duty to learn what pleases him and what doesn't. We will be questioned about it.

Allah says in Quran 

Say: Shall We inform you of the greatest losers in (their) deeds? It will be those who labor a great deal in this life but without guidance, yet think that they are doing a great many good deeds.

[Al Kahf 18:103-104]

May Allah not make us one of those people Ameen. That is the reason I ask and tell everyone to check the deeds you are doing no matter how small whether they are good deed or not, are they according to the teachings of Prophet or according to teachings of some Maulvi or Alim or is it just your customs.

In these times it's hard to tell a Muslim brother or sister something or ask them that why are you doing such an act, they get defensive although maybe the one asking might be rude or asking in a way which is not good but we should remove this barrier and try to correct ourselves and others and should listen to what others have to say and explain in a nice way. This doesn't mean that one should point things out in public rather it should be done in private.

Abu Hurayra said, "A believer is the mirror of his brother. When he sees a fault in it, he should correct it."

Al-Adab Al-Mufrad 238 (Hasan)

One more thing should be kept in mind. In case of acts Allah has told us exactly what should be done, He told us to do this and this and this but in case of worldly matter like food or other things He only told us that these these things are Haram rest are by default Halal. So some of the people use the second rule to justify their deeds, that the Prophet didn't told us not to do this deed. This doesn't apply to acts ( maybe I am not using the right word maybe it should be the things which are in unseen) Prophet SAW told us every act which are right the rest are forbidden.

O Allah! Enable us to see the Truth as Truth and give us the ability to follow it. And show us the falsehood as false and give us the ability to refrain from it. Ameen