Then he came up again and said: 'This report isn't very good'. I would have justified myself before, which is what most people do with bullies. But instead, I said: 'You're right, it's not very good. Maybe you should get someone else to do it'. I wrong-footed him, and he never bothered me again. But nice people fall right into the trap."
Ms Gryzb, a trained psychotherapist who started her career marketing the New York City Ballet and worked alongside the Royal Opera House's Mary Allen, now helps "nice people" eradicate bowing and scraping habits and to develop their full potential in the workplace. Eight years ago she set up the Impact Factory with actor Robin Chandler. The pair had a brainwave one Christmas.
Ms Gryzb recalls: "I had just split up with someone, and I told Robin I was tired of the way I was with men and that I didn't like the person I was turning into. He was dealing with some of the same issues and put it down to the nice factor. We both looked at each other. We created the course in half a day."
"The Nice Factor", which subsequently became a book and has now developed a sister course called "The Nice Factor At Work", goes beyond the standard assertiveness training, which, Ms Gryzb claims, doesn't often examine the roots of "people-pleasing".
"Most assertiveness training courses are for women," she says. "It's much harder for men to say: 'I'm not very assertive' than 'I'm too nice for my own good'. When we started the course, I wasn't expecting to get people who were intimidated of their own secretaries, too frightened to ask them to do the photocopying."
Impact Factory, which counts BT, Christies and Glaxo among its corporate clients, tailored "The Nice Factor At Work" to concentrate more on resolving problem situations through role-play than on past influences.
"A lot of people don't want to give up that softness, and we don't want to make them strong, stand-up-for-myself type people. We are trying to get people's awareness to a level where they have the possibility of changing."
Body language, says Ms Gryzb, attracts bullies and extra work like a magnet. "The big boss will come in, look around and say: 'Who am I going to get to do this?' They know it's going to be an easier ride with a nice person."
Smiling, avoiding eye contact or fidgeting while giving an assertive verbal message can all be counteractive. People who are nice at work often take out their frustrations at home, or they can lie to themselves, saying: 'I didn't really want that promotion'," says Ms Gryzb.
She describes the attitude she has encountered in Britain as commonly a mix-up between politeness and niceness. "Politeness really does oil the wheels, but over-niceness is apologising for just being here," she says. Sometimes, nice can flip quickly into nasty. One course participant, an IT helpdesk manager for a financial company, would come in early each morning, but would occasionally blow up and scare workmates. "He didn't know how to say no; he had to learn the difference between urgent and important," says Gryzb. Another woman took the course because she couldn't face firing a subordinate, while one man in his twenties came after his protector at work left. Some participants are sent by managers to toughen up; others at the top of the tree need to survive in an ever-more-ruthless business culture - but cannot give up nice habits.
Gryzb claims her methods work: she receives letters from clients thanking her for the changes the course has wrought. "In two days you can accomplish a lot. A huge amount of talent gets wasted by people not being fully in their individuality, and part of the pleasure of running these courses is to see that working."