I just can’t believe how many people have difficulty with the word JUST. It is one of the most misused words there is. It is used incorrectly most often when used in combination with another word. Can’t is the most common one. This topic never came up in any of the linguistics courses I’ve taken so I figured I would take it upon myself to educate the masses. I have not done a full linguistic analysis to technically demonstrate the differences but trust me, they are different. For now I will try to highlight the differences by giving examples. One note, the ones I can remember right now seem to be negatives which may mean something or not. I’ll have to try to remember some others to check.
The phrase “can’t just” is very different from the phrase “just can’t”. Respectively, one is exclamatory, the other is explanatory. Saying “I can’t just walk in there.” means that you are capable of walking in there but it is not easy or appropriate for some reason. For example, you may need identification or you may not be dressed appropriately. It gives an feeling of resistance. Saying “I just can’t walk in there.” means that you are unable to walk in there even if it were possible. For example you may have a broken leg or the doors may be locked. It gives a feeling of helplessness.
The phrase “don’t just” is also different from the phrase “just don’t”. The former is a statement minimal requirements while the latter is a statement of fact. For example saying “You don’t just go out and buy a house.” means that you cannot just go out and buy a house because there is more to it than that, and that buying a house requires more work, planning, research, etc. beforehand. Saying “You just don’t buy a house.” is an unquestionable factual declaration indicating that you cannot or may not buy a house.
There’s several other combinations (like can’t and don’t) where just is usually used incorrectly but I cannot remember them right now. I’ll add them to this post as I do.