When people become "emotionally involved" with their client is often happens that they share an emotional problem that has not been resolved. If a counsellor has a trait of "anti-authoritarionism" and a client has problems handling his boss because of is "antiauthoritarianism" then it may be difficult for a counsellor to help his client handling his boss.
The difference is between empathy and sympathy, which has been explained in the
Counselling Communication Course
It is difficult for a counsellor to empathy with a client if a counsellor has never experienced a similar emotional experience. On the other hand when a counsellor has not undergone therapy, he/she may fall into the trap of a sympathetic relationship that sometime can be damaging to both client and therapist. Neither has an appropriate answer to a problem, they share. Counselling often implies a confrontation of different ideas that helps to solve a problem.
Sluagh's analogy of having two anchors - one firmly planted in the ground and the other in the air - is quite appropriate. In TA we used to say that one part of our mind should remain in the ADULT ego state and the other in the emotional states of either PARENT or CHILD. This comes to the same thing.
When you work in a "counselling" organisation, you will have ample opportunities to discuss your problems with other fellow counsellors. When you are being trained you will have or in a position to choose a supervisor who can help you with these kinds of problems.
Counsellors have to do a lot of work on themselves, but good counselling is never painful. The ah ah experience can be quite exhilarating.
Enjoy your counselling training course.