space before certain punctuation marks

Question

Quite often my written answer is marked wrong simply because I failed to insert a space before punctuation. I am trying to train myself to add the space, but it does not come naturally for me when I write in English. Why do you insert a space before certain punctuation marks, notably exclamation, colon and question mark? For example: This sentence ! and This list : and This question ?

It seems you do not insert a space before other punctuation marks, such as period or comma, for example:

Like this, or Like that.

Why ?

Accepted Answer

The 'why' is just "because". Why don't we include an extra space in English writing generally ? 
Don't waste too much time on punctuation in these exercises - they are not the best way to learn it, as you are presented often with fragments that make it even more difficult. The exercises are self-marked - so only you can mark yourself 'wrong". As this question has come up before, there are other responses and links to more on punctuation if it is a major component of what you want to learn.  
https://french.kwiziq.com/questions/view/space-or-no-space-before-the-currency-
https://storylearning.com/learn/french/french-tips/french-punctuation
https://www.lalanguefrancaise.com/articles/les-regles-de-la-ponctuation-en-francais

Answer

Thank you @maarten for the answer.  I get it.  Punctuation would be a fascinating study ! !

Answer

p.s. this link is no longer available: https://www.iwillteachyoualanguage.com/french-punctuation

Answer

Hello Observablebear, 
I have added a couple of links to Maarten's answer which I think will feed your curiosity.
Bonne Continuation !

Answer

Turns out, the rules are well-defined, even though not everyone follows them.  The links Cécile posted above or below are very helpful and I found this one useful too: https://www.frenchtoday.com/blog/french-grammar/french-punctuation/