Here's the thing about nice guys: There's such a thing as too nice or even creepy nice. If a woman thinks you're coating everything in sugar for her just to get laid, it's not going to fly over well. And honestly, in a lot of cases, the guy ends up inadvertently becoming a pushover from bending over backwards so much. It's unattractive. It's even more unattractive when the 'nice guys' start to whine because they're not getting any tail or emotional attention as it comes off as very infantile.
There is such a thing as being gentlemanly while still maintaining structural integrity.
Women are very complex and tend to be multi-faceted when it comes to their mental and emotional needs.
Super nice? Boring.
Super dickish? No long term (and in many cases, no short term) interest.
Super anything? Too excessive or dull.
Attracting and capturing a woman's long-term interest is a balancing act between intensity and grace.
When I speak of intensity, of course, I'm speaking of passion. Not necessarily romantic passion, either: passion for your principles, passion for your beliefs and convictions, passion for your endeavors, etc.
No woman wants a chump with no opinions of his own and no direction in life.
Have you ever spoken to someone that responded in pathetic one-liners no matter what topic was broached? Someone that's still the same d*mn person they were in HS despite having years of life under their belts? Someone that just agrees with whatever you say because they want to appease you? Someone that's the definition of stagnant both mentally and emotionally?
Those types of people are boring as friends, let alone romantic partners.
A woman has to know you have something other than her going on in your life, you know? She's important, absolutely, but you're your own man. A healthy relationship between two individuals should look like two broken pieces being seamlessly glued together as equal yet separate parts. You have to bring things to the table that keep her engaged, point blank.
As far as the grace aspect is concerned, I'm referring to simple but poignant behaviors: respecting others, holding open doors, genuinely listening, knowing when to be firm and when to be compassionate, being helpful to others, etc.
Being nice is not only fine, it's a necessity. It just can't be the only thing because there's a hell of a lot more that goes into the cocktail.