Scheme sucks

Most Lisps specify an order of evaluation for procedure arguments. Scheme does not. Order of evaluation—including the order in which the expression in the operator position is evaluated—may be chosen by an implementation
that is why.

>>1
The Scheme standards are the least common denominator of Schemes, half of the language is optional, even tail call optimization, nobody is around to care. Don't write Scheme code as if its C++ and you'll be fine.