These reasons are my personal and random thoughts. In points only, no details. In case you would like to know, let me know.
1. In search of better job
2. For more income generation
3. To help family or relatives
4. Attraction to bigger market
5. Better living standards in urban areas
6. To make new friendship with different people
7. Wide variety of food items
8. Better and available facilities
9. To experience the urban lives
10. Influenced by urban dwellers
11. In search of life partners
12. Enjoyment of sex
13. Notion of more happiness in urban areas
14. Attraction to infrastructures
These are just a temporary shed of short lived happiness.
Reason for not liking Rural Areas
1. Less job opportunities
2. Less income
3. Too much of manual work
4. No drayangs and no discotheques
5. Minimum facilities
6. Working in the field is tiring
7. Because of frequent woolhas and zomdoos
8. Unhealthy environment
9. Fade up of the local norms
10. Feeling of dissatisfaction
Actually, lives would be better without those regularly drayangs and discotheques. It has more disadvantages than advantages in my brain about it. However, I never mean to hurt the hearts of those fans of drayangs and discotheques. Your life, your wish.
Given a chance, everybody likes to live in urban centers despite the difficulties faced. Out of 100, may be 13 would chose to stay in rural areas if there is same provision. Nevertheless, our country is in higher rate of modernization. Our rural areas are developing.
All in one, the reason for Rural-Urban Migration is because of better facilities and more opportunities in Urban areas which is indeed a very illogical thinking of those migrates.