I'd rather struggle to get strangers than book friends easily. Friends (and family) tend to expect the shoot to be free when you "don't need the money because you already have a day job." That, and you're a friend: what are friends for?!?
Oh and by the way, even if they're just work colleagues, they'll not hesitate to call you a friend when they think it'll get them free photos. They may only see you in passing once a week at work but they're your buddy when they think they can squeeze you. Any kind of "connection" they can think of, they'll work it.
If they actually pay, it'll be a pittance and life will be miserable. If you do it for free, do it on your terms and tell them it's ONLY for portfolio.
Total strangers and friends of clients? Never a problem. They already know there are going to be costs.
Yeah, it's a Catch-22. Need work for referrals, need referrals for work. Gotta start somewhere, etc. But trust me - you don't want to work for friends or family or co-workers.
Hm, interesting. I guess it depends on the situation & the "friends" as I have never done a free or discounted shoots for friends from my kids schools, etc. I have charged everyone full price (and my sessions are not cheap - mid price range) & no one has asked for a discount because they believe in supporting me and my business. 

