In order to love somebody, you must get to know them and become emotionally intimate with them. And that takes time, amirite? And no, understanding and friendship can never happen in a moment, it takes time to develop, through mingling and spent moments.
Love based on first impression has no depth ; that is infatuation. True love develops from friendship.
Love never happens in a day; it develops and grows. 😃
your constant insistence of love not taking place in one day is proved wrong by God himself who makes almost every mother start loving his/her child the moment she becomes aware of his/her presence in her womb. If your logic would have been true, then a mother won't have loved her child till he/she is in his/her 20s and capable of taking care of her. in fact, she would have hated her child during his/her childhood for driving her nuts with constant tantrums. But that does not happen, right. A mother's love is the purest and most unconditional love on this Earth and it starts in a single moment and remains all her life long. it does not take years to develop. So no only care and respect for a person grows over time, not love. Love can happen in a single instance. it can grow with time or fade away with time, but it usually does happen in one moment only.