I am sure they could. :)
The one I am talking about was not smart, secure or skinny. She was fake, shallow and not mentally "there", so to speak.
It's not that I can't participate in others activities, more of that I don't want to.
As for being a stalker, at times it can make you the happiest person or depressed depending on how your relationship with your person of intrest is. For example, one day I woke up to a "good morning" text, that included a picture of her and her hopes that I have a successful day. I drafted that message and that was 2 years ago. It's still there. When you care for someone that much, a simple sentence from them can blind you with happiness.
On the other hand, being a stalker will make life miserable. I had a tedious surveillance routine that included checking her facebook, twitter and tumblr 3 times a day. I also screened her closer friends and relatives once a day to gain insight on any problems she may not be so forthcoming about. I texted her once every 23 days, just to keep my name floating in her head and to gain long term credibility. I would even date some of her friends simply to get closer to her and that within itself requires another set of background checks and relations.
All of this work and then you realize it's been 4 years and that all of this will amount to nothing. The fact that when I die my last thoughts will be of her and she won't even think anything of it besides the loss of a distant friend. The fact that I am physically, mentally and financially superior to any man she has dated but yet I can only watch. The simple fact that she is everything to me and yet I am nothing to her. the fact that when I'm old and gray, I'll still be here.
The best way to summarize this is to a stockbroker who has sold everything he has and will ever have for this share that is constantly sinking and he is just riding it out because he can't afford the loss.
If all it took were charm and confidence to get her, it would've been done.
One of her close friends became lesbian and jealous. Afraid I would take her, she concieved lies. Whether the lies were true or not doesn't matter to my target, because of the effects of this lie she suffered a considerable cost that can't be given or earned back.
So you see, I can't express through words about how I care for her. It must be shown through my actions.
As for the rest of your question I'm actually content with my life now and I'm not entirely sure what a borderline personality is.
Edit: If this is a accurate description of BPD then no. I'm almost the complete opposite. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001931/#adam_000935.disease.symptoms
People who are commonly referred to as 'pyscho' are often low functioning 'borderlines.'
I fit some of the symptoms.
Narcissism, stalking, lack of empathy, perfectionism.
Not enough to claim the title though.
Edit: I'm the far from low functioning. Never found breaking the law exciting or saw any rationality in emotional outbursts. I'm the opposite of spontaneous, I plan so much I'm mistaken as a paranoid individual.(my username comes from this trait)