Optimistic vs. pessimistic

Which type of person usually ends up in the better, longer lasting relationship?

The girl/guy who is too naive, too optimistic, too trusting & too quick to jump all in

OR

The girl/guywho is too cautious, too pessimistic, too insecure, too skeptical, too closed-hearted?

Half the people who can't find a "good" man or woman are told that they need to lighten up, be a little more trusting, realize that everyone isn't out to hurt them & stop being so insecure. The other half is advised to be more careful, be more cautious, have higher standards & not be naive. Of both women/men, which is most likely to end up in a better quality relationship IF they actually take the advice given to them?

I guess there's a few ways of looking at this:

1. The person whose too trusting will of course get hurt more often b/c the more people you invite in your life, the higher your chances are of getting burned by atleast a few of those people (for every 50 people you let in, 25 of those people will probably hurt you vs. the pessmistic person only letting 5 people in & only getting hurt by 2 of those people)

2. Then again, the person who makes everyone go through a dreadful pre-screening process to "get in" is at a higher risk of getting played/hurt too even though they allow less people to enter their heart, simply b/c people eventually get tired of being over-worked & feeling like they'll never win you over no matter what they do to earn you

3. The person who is more pessmistic may be a bigger pain in the ass BUT b/c they've got higher standards, stick to their guns & won't allow just anyone in, when they actually DO find a good relationship, it's set on very solid stone, which in turn makes it more likely to last alot longer

So who usually ends up the winner vs. the one who remains single forever?

The pessimistic insecure cling-on types always seem to have someone. How happy is everyone?
Some people aren't happy unless they are making someone else miserable.
In their minds I guess that makes them the winner.

Remember opposites attract?

Answer: When Exhibit A meets Exhibit B.
A The girl/guy who is too naive, too optimistic, too trusting & too quick to jump all in
B The girl/guywho is too cautious, too pessimistic, too insecure, too skeptical, too closed-hearted?

Otherwise, A and A or B and B will likely pass like ships in the night because they're too alike.