It is beyond crucial that you as an author find a way to make your character someone the readers can relate to and can at least like. If you don't do this, we will quit reading.
One of the things I have often found in romantic suspense novels in particular are the heroines who simply do stupid things just to get them into a situation where the hero has to save her. When I see things like this, my first thought is "Give me a break. She deserves to be locked up or getting in trouble." I really never even want to see the hero save her.
The same thing happens with many romances where the author is trying to go for the Beauty and the Beast trope. There is nothing wrong with this trope, but frankly, if he is that much of a jerk in the beginning, the readers will want to do everything in their power to find her another guy. Heck, any guy will do as long as he is not with this jerk. Again, not the thinking you want for your readers. They will give up.
I think an easy approach to take when writing your stories is to ask yourself if you would even want to be in the same room as your characters. Would you invite them to a party? To dinner? For the romance side of things, would you want this person naked and in bed with you? You can keep some of their smaller character traits, but make sure that you still keep the person likeable. Even if the person comes across as cold in the beginning, make sure to give the readers a justification for why the person acts this way. It doesn't have to be much, but it needs to be there.
I remember reading one historical romance in particular where the hero was a complete jerk. He treated everyone poorly, he had an attitude and so forth. I want to say (it was a while ago) that he was even a thief. I really liked this particular author's writing but frankly, this guy was really turning me off. It wasn't until roughly chapter 4 that the author finally revealed that this was all an act because he was working undercover. Really? Had they told me that in one line in the beginning of the book, I would have been fine. Sure, the heroine doesn't need to know, but the readers do.
So, your homework today is to really examine your characters.
- Are the heroes jerks?
- Is the heroine whining all of the time?
- Is she that much of a social misfit that no one would like her?
- Is the hero someone who is far from attractive (both physically and emotionally)?