Why is this happening?
Many people are really easier to do something instead of someone, than to explain why they can not do this, even to the detriment of themselves. Inability to deny is peculiar to people soft, kind and hesitant, having low self-esteem. They suffer from their own "flawedness," but they do not dare to protest persistent "petitioners" for fear of offending them inadvertently. Absurdity, but many ladies inability to refuse "such a good man" led to the crown with an unloved man. We all want to look better in the eyes of others than we really are. But some in this one's desire to be good for everyone go so far as to forget who they really are. They lose their "I". And having acquired the reputation of a reliable and kind person, on which you can "ride", and with complete impunity, suffer from this state of affairs, but they can not change anything. As a rule, "failure-free" are those who were "disliked" as a child. Too strict parents or their lack of a child's life doom him to the fact that he will then try to earn his love all his life, including without fail fulfilling the requests and desires of other people.
What if people used your kindness to become familiar? Statistics argue that most often good people can not refuse a request to their boss, a handsome man and colleagues at work. Well, with the boss everything is clear - it's more expensive! With the man you like - too (suddenly appreciate not only the ability to use a copier and correct grammatical errors, but your beauty will notice). Colleagues also do not want to offend - all of a sudden some day their help will be needed, and it will be uncomfortable to approach and ask. Although, according to psychologists, good people who do not refuse anyone, themselves, as a rule, very rarely seek help, preferring to cope on their own. Inability to say "no" can lead not only to complex personal experiences, but, oddly enough, to conflicts at work and in the family. Constantly distracted by the requests of others, you can easily overwhelm your part of the work and cause this resentment of the authorities and discontent of employees. Fear of refusing a man can hurt not only you, but also him: your good behavior, he will be introduced into a pleasant error for him, the way out is not so pleasant. The ability to say "no" is a sign of a mature personality. And until you learn to refuse (of course, in a soft form and preferably with an explanation of the reasons for the refusal), you will hardly be able to get rid of the feeling of discomfort. However, as well as feel like a man mature and held.
I do not want to be a riding horse!
The next time you feel that you are "riding", take advantage of such advice from psychologists. Ask why it should be you. If the explanation of the applicant seems to you unconvincing, do not be afraid to refuse or recommend someone who could fulfill the request. Your answer should be brief, without any lengthy introductions and explanations for the reasons for the refusal. If you find it necessary, you can explain the reason for the refusal. But it is to explain, and not justify and not apologize in this case.