C#

Reference types are nullable by default; in-language null keyword is untyped. Lack of discriminated unions Exceptions as default, non-exceptional error handling method - there's not much of an alternative. archaic switch statement syntax and limitations Needless distinction between constructors + static methods Static methods can't be part of an interface Lack of by-shape interface implementation rather than explicit interface implementation - leading to numerous language design hacks such as the linq query syntax, foreach, collection & object initializers -- none of which can be flexibly reused. For example, the object initializer syntax may be nice, but plays poorly with immutable objects. Cannot inherit "interface" of a class independently of implementation - leading to code duplications and overarchitected code that provides interfaces, abstract base classes, a few common implementations, and no way to pick and choose the bits of each to use. Also; leads to too many code that's tightly coupled to a particular implementation since it's common to explicitly refer to the implementation type rather than an interface. Cannot multiply inherit via composition since a classes "interface" is tightly coupled to it's implementation; effectively lack of mixins. The above limitations of interfaces lead to a proliferation of virtually identical interfaces that don't overlap naturally in any kind of type hierarchy. IComparable vs. IEquatable vs. IComparable<T> vs object.Equals vs. operator == etc. etc. By extension, making a custom type that satisfies all these things is a lot more work than necessary (in particular for collection classes). Obviously, the language designers realize this, hence the various workarounds for things like linq, foreach and collection initializers which work by-shape rather than by-interface. Redundant use of parentheses and braces rather than layout-is-structure. Return values can be ignored, limiting the effectiveness of type inference. Enums aren't a normal type and can't have methods. Also, enum values aren't typesafe and may be initialized to 0 despite not having a 0 value. Mixing metaphors by lumping flag and non-flag enums together. Lack of proper value type support. Value types can't be inherited, have different constructor semantics, and perform poorly due to CLR limitations. Also, confusing semantics regarding value types: some values are really values (and can't be modified), and others are really non-aliased, non-null references (variables). This gets particularly confusing with regards to the next issue: Semantic distinction between fields and properties, particularly in conjunction with lack of mutability modifier (ala C++'s const) Can't specialize generics Cannot provide default generic type parameters (e.g. factory generics) lack of typedef makes generics a pain to use (using is a limited but good-to-know substitute!) Can't genericize over things other than types (e.g. functions, plain values, or names). This means you can't do something like make a generic implementation of a dependancy property leading to, well, nasty implementations of things like dependancy properties and the overuse of code-snippets and poorly readable code as a result. Limited capability to specify generic type requirements e.g. generic sum method that takes both int, double and a bigint (without tricky and often slow hacks). An interface method implementation or virtual method override cannot return a more specific type or accept a more general type; i.e. limited co/contravariance support even in C# 4.

Ruby。

Strange scoping rules - variables, constants, and methods each behave differently from each other. The rules change also depending on which keyword you used to create a closure. Or on whether you're in a class, eigenclass, object, module, or module's self. Then there's instance_eval, which changes the rules to a different set of rules. And they change again when a module is "included" or "extended", which themselves do different things to scope. And some sets of rules can't be emulated by metaprogramming, so you have to use eval. Unless you're on ruby 1.9, where all of this is different. Namespacing is basically useless. If you have Foo::File, then the stdlib File is probably broken for all of Foo. require statement is broken. If two files require eachother, the behavior of those files can change dramatically depending on which is loaded first from elsewhere. libraries change APIs dramatically and suddenly, so you have to require specific minor revision numbers of all of your dependencies. For every single ruby application on your system. The rubygems package system overrides "require" rather than putting files in the search path - because why use a system when you can replace it?

Lua

我喜欢用Lua编程，但下面是让我头疼的事情:

没有办法用这种语言编写API——不像C .h文件或Java接口 语言有一流的功能，但有人忘记告诉设计库的人。 编写函数的语法太重量级了。 语法分为语句和表达式。 表达式形式是贫乏的:没有let形式，没有真正的条件表达式，……

尽管如此，我还是坚持认为Lua非常棒:-)

ColdFusion

大型Flash表单的编译时间。 动态变量类型(有时我讨厌它们) CFScript缺乏特性。 CFTable(永远不能正确显示)。 CFChart中缺少图表类型。 完全缺乏NTLM支持(企业就绪-是的) cfc中的低能变量作用域 没有一个真正的NULL的概念-你的变量只是消失! 没有办法测试某些东西的存在(比如作用域，只是它们内部的成员)

C#

泛型参数是不变的，c# 4.0为泛型类型引入了协方差和逆变性 可覆盖的类成员必须显式地标记为virtual

Java

缺少无符号数字数据类型 基本数据类型不是对象

PHP

如果你不能控制服务器，就没有调试功能，即使这样也很糟糕 大量糟糕的PHP代码给所有PHP程序员带来了坏名声 不一致的函数命名 如果我想要一个静态类型变量，就不能有一个静态类型变量(我90%的时间都是动态类型的忠实粉丝) REGISTER_GLOBALS是魔鬼