Most Helpful Guy
I think there are probably different reasons for doing it. Some people just don't like being alone. It might mean they are not whole by themselves, but not necessarily. Some people just prefer being with other people all the time. Some women just happen to really like men more than most women, and want to be around them all the time. But yea, for some it might just be insecurity.
I have a neighbor whose husband died a couple of years ago. I think they were married for almost 20 years. I knew when he died that she's want to start dating again before long. I knew she was just the type who wanted someone around. Sure enough, after six months she started saying she needed to get out and date (with a slight hint that I was a prospect). Six months isn't long after a 20 year marriage. She's not weak or insecure. She's intelligent, is very capable of doing things and making decisions. She stands up for herself and is outspoken if she feels the need. It's just that she wants someone else around.
Most Helpful Girl
I think that these girls are very insecure, and they are not happy with themselves. Same goes for guys. It's a sign of insecurity. They aren't comfortable with themselves. They are reliant on others for their happiness, and are possibly relationship addicts (This is an actual addiction). It also shows that the person more than likely has low standard or no standards at all, because they are hoping into relationships just to be in them and not because they actually see the person as a potential long term partner.