Emotional involvement means being emotionally part of an activity, groups or circumstances. It brings your emotions in whatever activities, situations or circumstances you are dealing with.
Throughout the life, you come in contact with various things, which provide pleasure and comfort to you and drag your emotions in it. Although it is unrealistic to be emotionally involved with worldly objects and situations.
Hence, do not emotionally involve yourself with any objects and situations otherwise you will be completely devastated when the things get destroyed. For example, even your properties and positions are not going to remain with you forever. Some other person will keep hold of that properties and positions after you.
Emotionally involving yourself with things form a deep impression in your subconscious mind which in turn develop various biases and prejudices in your mind in favour of and against things. In addition, you make bad decisions due to your emotional involvement, which tends to reduce your ability to see things objectively.
In short, emotions are good as long as you are in control of them. If you want to enjoy the things and move on with life, make sure you do not get emotionally involved with things, which generate biased emotions of like, dislike, love, hatred, jealously, anger, etc. Give up your emotions, let it go in time and remain calm and balanced in life.