Change starts to occur the moment we accept something as a barrier to being good. 
We all have our own mental frames, like the frames of any structure. We have nurtured it until today, intentionally or otherwise. We name it our habits, emotions, beliefs, or the sum of our behaviors. Even if we agree not to retain some of our odd behaviours, we find them hard nuts to crack. 
Our friends, family members, and coworkers freely point out our shortcomings, but we defend ourselves as strongly as possible. We deny in toto. That is why criticism is a bad tool for making amends with anyone for anything. 
At times, we choose the option of arguments in a social context. This mechanism has also yielded no better results. Arguments put the people apart rather than getting two divergent groups together. Normally, the purpose of coming to some agreeable points is often missed. 
The therapist takes a different route. He is not mixing the problems with the affected individual while trying to locate the problems. 
An expert in psychology tries to see a person in terms of his or her memories, feelings, likes, dislikes, and fears. Thus, the therapist will assess the roots of problems and start working on them. 
Till a person accept he is habitually a late comer in office in meeting or at other places, no other formula will make him or her punctual. Once he feels simply ashamed, it will serve as medicine to initiate change.
It is realisation that works wonders. To the extent we defend ourselves for all our wrongs, situations remain the same. 
It is also true that we are punctual for a few days and go back to our old pattern of behaviour soon. It happens. We have to remind ourselves that we have to be punctual, even if the majority are careless about attending any engagements on time. 
Mobilizing our inner power is the best remedy for transforming us into new individuals.