Typical requests and how to refuse and say no them :

Here are some of the few daily life examples of how you can refuse requests effectively :

• When someone starts talking about a problem that you could potentially help them with but you don't have time to handle and is not your responsibility: "Wow. I can really understand how that would be hard. (Then     say nothing more—just nod, smile, and release the problem when you walk away.)      
• When someone asks you to do something that your much-less-busy coworker could do: "I would love to help you out, but given my schedule, I wouldn't be able to get this back to you for a couple of weeks. If you would like to have this turned around sooner, I recommend that you reach out to __________. Does that sound good?

• When you're given an exceptionally short deadline:" I know this project is a high priority for you, and if it's absolutely necessary for me to turn something in by that date, I can make it happen. But if I could have a few more _________ (days, weeks, etc.), I could really deliver something of higher quality. Would it be possible for me to have a bit more time?

These are some the ways that a person can refuse without directly saying no of the face of the other person and also setting boundaries that not all of the requests can be accepted.

*Elizabeth Grace Saunders . Retrieved from http://99u.com/tips/7076/Setting-Boundaries-Saying-No-Nicely

It surely feels good to be in that situation where everybody comes up to you and say that "can you please do this work i couldn't get it done and you cant resist but to say yes .The feeling of being appreciated and called that "I just don't know what I would do without you" is surely makes you feel the importance of yourself .
A good guy syndrome is what it is called .
But the problem with this is your own important work and time for yourself is gone ,you end being more stressful then you ever will e if you would have just said no that time .

Saying yes is not a bad thing we should always up for helping people if they need us but it should not be at the cost of our own work and energy .*One more side effect of "cant say no" is people are less likely to take no from you and a result they develop the habit of always hearing yes from you and the moment you say no they are more likely to get offended then not and this can sour up the relationships between you and the requester.