Eating cookies is nice momentarily but doesn't solve any problems in the long run. Cleaning and studying might be boring but in the long run will make you happier. You get a comfortable home and you finish your exam and hopefully get a well-paid job if you manage your studies. When you have completed a difficult task, you will feel a more lasting feeling of happiness than when you have eaten cookies.

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Working on your way of life; Creative problem solving
How can you improve your way of life, by solving problems?
Changing Yourself Step By Step; Coping with problems
It is easier to succeed with changing your lifestyle if you divide the change into many small steps, taking one when the previous has succeeded.
How to change your eating habits.
How can I change my behaviour?
Self-Change and Tobacco/Alcohol Addiction Treatment; Quit Smoking Help
Yes, in fact most people get rid of addiction without help from someone else! This answer gives quit smoking help.
Assertiveness, Communication skills
What is Assertiveness? How do I learn to express my needs and rights? How do I develop self-esteem?
Life and Relationships Links; Relationship Problem Advice
List of links about solving problems of life like relationship problem advice, changes, grief.
Problem Solving Techniques : how to solve personal problems
What is a systematic approach to problem-solving?