If I lose my temper, will my counsellor start to dislike me

People often worry about the feelings of their counsellor and whether they might be upset or offended by what happens during sessions. Most counselors will attend professional supervision sessions to discuss their clients (in confidence) and to deal with anything that has come up during the course of their work. This means that they are responsible for their own state of mind, and should be able to take care of themselves. This does not mean that counsellors do not have feelings or never have strong reactions to what is said to them. Some may even be keen to tell you how they feel, whereas others will be more reserved. This usually depends on the kind of talking treatment in which they are trained. If you get very deeply in touch with your own emotions during a session, it is possible that you will feel a lot of anger or sadness. It may seem to you that showing these feelings would be “offloading” them on to your counsellor. But there is a clear difference between displaying sadness or anger about an event or a situation in which you find yourself, and acting aggressively or threateningly towards your counsellor. Getting annoyed, raising your voice, or even shouting may be perfectly acceptable if these actions are not meant to scare, to shock or threaten the counsellor.
To some extent this is a cultural issue, because some sections of society are more comfortable with emotional display, and some are less so. Counsellors may have different ideas about how feelings are best expressed, but they should be skilled enough to accept your feelings without judging you. This does not mean you have a licence to attack your counsellor verbally (and certainly not physically), but it does mean that you can expect understanding and compassion about what you say and do when overwhelmed by your emotions.
This may give the impression that big emotional scenes are normal in talking treatments. A more accurate way of looking at it would be to say that they are not at all unusual, and are neither something to be aimed for nor something of which you should be ashamed.