Gonna provide examples this evening. But first of all :
It's because i'm french.
In france we don't put space before "," and "." but we do before "?" and "!".
But I do think in english, although we don't put one before "?" and "!", we don't either before "," and "." ?
And as I tend to speak french and english everyday I tend to mix both.
Also I do feel weird when I don't put one before "?" and "!" so even if I know I should I sometimes consciously don't :p