The workplace as a good place to make friends?

Yes and No. They're good people to talk to because you're working together for a common cause, and they'll probably like you for being a reliable worker. But outside of work that's tough to say, because then the context changes. They may not like the same activities that you enjoy, nor have the same views as you do. I would lean to the side of no.

if you can, you should not forge close relationships with coworkers... IMO.

BUT... if you're desperate and lonely , as i am, and a coworker happens to be an interesting "friend prospect", then why not try to make friends?

Well my current friends are people I met at work. I don't socialize at bars, clubs, etc. And at my age kind of difficult to make friends when people at my age tend to be married with children. So their life is consumed by spending time with the wife/husband and or kids. My 2 work friends are basically just that. I've hung with them occasionally outside of work, but they're married so most of their time is spent with their wives. So I'm kind of a 3rd wheel sometimes. But yeah if it weren't for work I probably wouldn't have much in friends.

ive always found workplaces the perfect place to make enemies. In my experience, enemy free workplces dont exist.

Depends. You can make friends anywhere, even the local homeless shelter or the subway.
Properly picking those friends, therein lies the real trick. There's likely places and unlikely ones, but then there's good and bad people. Placing trust in the proper receptacle is where the real challenge lies.