Common good

This term sounds to me something like this:

There is probably no common good if some doctor or his assistant shows to other patients or to other people all problems of one of his popular patient for example diseases of a public person like politic. From the other side probably is for common good to show on such doctor with the purpose to protect the other patients.
Another hypothetical case of 'not for common good' doctor is a doctor who tried to make a mental patient from someone, because this someone has been particularly and non voluntary involved in some corrupted deals or other half legal kind of business and can be danger for this business but maybe not for taxpayers. The doctor probably did all this with intention to protect other parties(or parties) from his/her lobby of course. Hypothesis is only hypothesis but if there are proves then is probably for a common good to show on him/her especially if he/she is a public person and his/her doing has totally nothing with a program of political party he/she belongs to.
The doctor I've mention in second hypothetical case, probably done all this for common good too, but in his/her 'common good' major part of population not seems to me as included and this is the main difference.

Next association of term common good could be illustrated on the case of for example small country which one has a small industry of weapons. Probably there is no common good if somebody shows to others maps of factory and plans of very secret parts of weapons for self defence. All we know there is no common good.
But, from the other side if this small country supports(p.s.) or it was supporting some kind of terrorism some time ago and at the same time shows to others itself in totally different light and this country for example owes a lot of money to others, it is receiving a lot of financial help from various founds, shows to other its nice and good prepared laws, have nobody who respects these laws and nobody to protect these laws, than probably is for common good if we are showing on that country with a purpose to protect other people and their investments in that country. There is a good reason to do that for common good, I belive.

Well it's enough about definitions of common good. I'm technician may be I'm wrong, it's a little bit different from data bits but I think I'm right, over all I've seen the world from this and from the other side and I belive that I'm right.