When creating characters for your story you should think of yourself as Dr. Frankenstein. Just as Frankenstein brought a creature to life from the sum of various body parts, you too are giving life to a character that doesn't exist. And, in order to do that, you're taking different parts from your own imagination and experiences to create a being that your audience can believe is "Alive!".
Sometimes writers get so lost in the creation of the story that they forget that the characteristics they've implanted their character with won't allow them to do certain things. The psychological elements are usually missing altogether in most Bollywood films. For example, if you take a character like Chulbul Pandey from Dabangg, there are certain nuances and body language which the character resonates. Chulbul would never behave the way Prem from Hum Aapke Hain Kaun..! would, but that doesn't mean he can't have his own love story, it just has to be in his own style and must follow his mental state.
Having said that, this doesn't mean your character(s) can't do things which are out of character, but a situation has to present itself and it must be brilliantly written. For example, If the spouse of a lead characters were to die or be killed, there are different paths the character could take if it's a male who has suffered the loss; and if it's a female who has lost her husband her mental state would be entirely different.
I always recommend to new writers that they take Psychology courses or at the very least read a few books on the subject. It helps you as a writer to understand how a persons mind would react in any situation depending on their mood, situation and surroundings. For example, if your character is in a situation where he's being bullied, there are several scenarios that can come into play, depending on the type of character he is, he could 1) do nothing or 2) turn it into a humorous situation or 3) fight back, etc. it's important to know which one because it will define him to your audience. And if you choose the wrong scenario the audience will feel cheated and your character will become a farce.
It's not easy to write a brilliant story or screenplay but it does make it easier when you have a solid understanding of all the parts that make up your character(s). If you write ignorantly you risk facing the same fate as Dr. Frankenstein, in your case the monster will be your story or screenplay. But, if you can write brilliantly you will touch the height of success Dr. Frankenstein only dreamed of...