All reduce/reduce conflicts and many shift/reduce conflicts are caused by ambiguous grammars. Beyond the fact that bison doesn’t like them, why are ambiguous grammars usually a bad idea?

Find a grammar for a substantial programming language like C, C++, or Fortran, and run it through bison. Does the grammar have conflicts? (Nearly all of them do.) Go through the name.output listing, and determine what causes the conflicts. How hard would they be to fix?

After doing the previous exercise, opine about why languages are usually defined and implemented with ambiguous grammars.