How are you doing buddy? Long time no see and I hope that you are doing fine these days. Unfortunately a lot of parents forgot these days that in the end the final decision should be for their children and not them. They forgot about the right meaning of happiness and run after shallow things that does not matter while they forgot about what really matters. I got a lot of points here that will go as:
1- The father wants the future husband for his wife to match him [Profession-Thinking-Habits] and some of them would go more far and offer you their house to stay there just to keep you under their eyes and make sure that you are treating their daughter good.
2- The father is very rich and can't afford to be the joke of his partners buy letting his daughter marrying for example a poor guy.
3- Some of them still believes in such old fashion traditions such as the Cousins are for each other, my daughter will marry no one but her cousin.
4- The daughter is the one who is working and paying for most of daily life expenses and the family is relying on her and if she get married, who would be taking her place?
5- Again believing in old fashion traditions, the younger daughter can't be married before the elder one. What would happen if she did not and she got like 4 or 5 younger than her?
6- The high percentage of divorce cases these days, afraid that his daughter would be one of those one day and will return to his house again and find no one to marry her.
6- Different nationalities and religions also can be an issue for some families.
7- Afraid that their husband won't make her happy and would treat her bad.
8- The husband is having lower salary, bottom line he is looking for someone [in the father opinion] not to support him, but to take care of his expenses.
9- The educational level of the husband or his profession is something completely different than his wife [she is a doctor then should marry a doctor, how come this guy is an accountant?].
10- The mother want the girl for her relative [her sister's son, her only god knows how this guy is even relative to her].
11- Both of the parents agreed on not to agree on him [someone says yes, the other says no].
12- His family is from one of the families that have some issues [criminal relatives or having always issues with others, but com'on ... the other family members should not be effected because of someone did bad things].
13- The father is leaving the country soon after reaching his retire age and want his daughter to be there in his home country in front of him when he goes back.
14- The father believes that his daughter should continue her studies before getting married [some husbands promised to insure that, but later they force their wives to stop] and he got the right to ask for that [spending money for like 4 years and in the last year getting married and stop? just unfair and a waste of money].

There are more KSA, but those are some of the reasons, not my reasons of course ... Not a father yet but would love to see my daughter ending up with someone who would love her and always cherish this marriage.

Take Care dude ...

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Do not dwell in the past, do not dream of the future, concentrate the mind on the present moment. (Gautama Buddha)