Bad Names

name why it's bad alternative
Fixnum obscure jargon Integer
attr_accessor "access" implies reading, not writing attribute
default block "default" is misleading anonymous block
default hash "default" is misleading automatic hash
case comprises many cases, not one case switch or compare
equal? compares identity (object_id), not equality identical?
yield implies thread/process swap call

and in Rails...

name why it's bad alternative
attr_accessible it's about setting, not accessing mass_assignable
html_safe its content will not be escaped in views html_dangerous or raw