I would like to share a story I have heard or read many years ago. And I'm sure my atheist friends won't be cross with me for telling an age old mythological story as they can surely take it to higher platforms and invent many more interpretations. 

Narada according to Hindu mythology is a hard core devotee of Lord Vishnu. He is supposed to be a vedic sage capable of travelling to distant worlds. Once he is said to have acquired inflated ego and started bosting that he is the most sincere devotee of Narayana, the Lord and that no one can excel him when it came to true bhakti, devotion. 
Lord Vishnu, when He came to know of Narada's pride wanted to cut him to size. 

One day Narada entered Vaikunda, the abode of Lord Vishnu, chanting 'Narayana, Narayana' as always. After exchanging initial pleasntries, Narada started beating his trumpet. 
“Lord, is there anyone in the whole of seven worlds who can beat me in my bhakthi to your lordship? No, and I'm naturally proud of this.”
The Lord did not reply. There he was with his usual mischevous smile which disturbed Narada.
“Why are you silent, my lord? Don't you agree with me?”
 “Oh Narada, when did you come? I didn't notice your presence as I was immersed in the bhakti of a true devotee of mine in the boologa(earth). Did you say something? Anyway why don't you go and meet him and come after a week or so?”
Feeling hurt beyond words Narada dashed off to earth and found the trader, the Lord mentioned and started observing him keenly. The man was a shrewd trader and went about his business as usual. He didn't even murmur the Lord's name once during the day, let alone perform any pooja. His mind was fully occupied in his business which he did honestly. 
He returned to his home after a hard day at work, had a wash and relaxed for some time. Then played with his children and went to bed after dinner. He got up early in the morning. After taking bath he went to the pooja room and lit the lamp and prayed for a few minutes, no elaborate pooja or anything, just a few words of prayer. Then he went to his shop to look after the business. The routine continued every day. Making enquiries with the neighbours and family memebers Narada could realise that this was his rotine, be it any ordinary day or festival or other special days. 
Narada could no longer contain his rage. Why did the Lord think this man is his true devotee. After all this man says some prayer for less than ten minutes a day and doesn't even think of Him for the rest of the day, whereas I am chanting mantras and prayers 24x7. Still the Lord praises this man. I should show the true colour of this man to the Lord. And he rushes to Vaikunda.
“Narayana, Narayana.”
“Hello, Narada, where were you?”
“Lord, I was observing the trader in the boologa as you said. He says a few words of prayer every morning. Whereas I am singing your praise all the time. How can you compare him with me?”
“Easy Narada. O.K. I shall accept you as my most devoted bhakta if you pass a test. First go and get a bowl full of milk kept over there. Bring it without spilling a drop.” 

He went within seconds where the Lord pointed and saw a bowl filled to the brim with milk. He wanted to please the Lord and took it in his hands after putting the narada veena  down. Normally he never parts with his veena, but he was prepared to do anything to make his Lord appreciate his devotion for Him.
He started moving towards the Lord. Though the distance was quite less and the bowl quite small, he could not walk fast as he could not afford to shake the bowl and spill the milk. As he was fully conentrating on the milk bowl, he didn't realise that it took him quite some time to reach the Lord. But alas, he made it. He had brought the bowl without spilling a drop out. He proudly placed it before the Lord and looked up.
“Thank you Narada. But where is your veena?. You look strange without your veena which has almost become a part of you.”
Narada ran back to fetch his veena and returned, chanting 'Narayana, Narayana.'
“Now my Lord, I have passed the test that you gave me. I hope at least now you shall agree that I am your true devotee.”
 “Umm..., wait Narada, just a couple  question. How many times did you chant 'Narayana' in this last one hour?” It had taken him an hour to accomplish the task.
He was silent as he hadn't for once.
“O.K. How many times if ever did you think of me during that time?”
Silence again.
The Lord smiled and asked, “So you forgot your lord so soon?”
“Oh Lord, but You had given me a task and I was concentrating on it,“ Narada tried to reason out.
“And I completed it as directed by you without spilling even a drop. I thought You will appreciate it.”
“That's good.”
Narada sighed in relief and quipped, “So, You agree that I'm Your true devotee?”
“Wait, My devotee the trader is calling me in his usual morning prayer. I shall come back to you after listening to him.”
Narada was shrewd. He didn't need to be told that the Lord valued praying for a few minutes every day in spite of his busy schedule more than a lazy man's day long prayer.