Relations

There are two types of relations. One is Blood made relation, and another is Time made relation.
Blood made relations are like father, mother, sister, brother, cousin, grand parents and all(family members). This type of relation is constant one(no change in love, love forever), you love your father means, you love him from the day you were born till the day of your separation(death).
Time made relation are those which are dependent on time, like friendship. As time pass by, the relations becomes stronger or weaker, according to the separation (distance between the two friends ). But there are some relations which grow stronger, even if the distance between the two is high.
So it is necessary for the relation, whose strength(love for the person) goes on increasing regardless of the separation, just to end increasing the strength. One wants to shift that relation in constant one, to the loved one, blood made relation, letting the person to become a part of your family. So the question is, why to choose only husband and wife, why can't it be brother and sister or brother in law and sister in law. Don't you love your sister, don't you want to see her happy. Love is all about to wish to see the person you love, happy.
And the answer is, strength of that relation(love for the person) is so much increased that you don't just want to see her happy, you'll do anything to see her happy, you want to be with her always. And among the given relations, in family only husband and wife stays with each other.
As, this kind of relation was time made relation, I don't believe in love at first sight. [:D]
Well now a days, we should think for brother-brother relations also :P

Excess

There is an old saying in sanskrit, "Ati sarwagya warjyate". That means excess of anything is bad.

We can handle things in two ways, one is using it and another is misusing it. Nuclear reactions can be used for getting power (electricity) and also can be used in nuclear bombs. One of my friend had some disease in which he was growing thinner. Doctor suggested him to drink beer, 3 teaspoons daily. Then for 5 years he drunk beer, which gave him no harm. Medicines have alcohol in them, for removing illness. But, alcohol taken in EXCESS is injurious to health. These things were created or invented for some good reason, but everything depends in the way we are using it.

Sugar(glucose) is meant for getting instant energy, but excess of it can cause diabetes. Excess of everything is bad. Teasing a friend in front of all other friend for fun is good and grow relations closer, but excess of teasing can make the person angry and can break friendship. Excess of gaming, sleeping, talking and even studying are also not good.

Sometimes excess of love is also not good[;)]. After a long time, when I went to my home, my mom fed me with all the stuffs, which she knew I like. I was trying to control myself, but, as love was involved in it so I couldn't say NO, and ate everything. And at last I vomited all of it out. Then she realised, its excess.