A discussion recently ended laughing at the bad habits of programmers that have been too exposed to a language when they start programming in another language. The best example would be a Pascal programmer starting to #define begin { and #define end } when starting to write C.
Goal is to try to catch the bad habits of C programmers when they start using C++.
Tell about the big don't that you encountered. One suggestion by answer, please, to try to achieve a kind of best of.
For the ones interested in good habits, have a look at the accepted answer to this question.