c# / .net:

Classes should be sealed by default There should be no lock statement - instead, you should have specific locking objects, and there should be methods such as Acquire which return disposable lock tokens. Corollary: there shouldn't be a monitor for every object. GetHashCode() and Equals() shouldn't be in System.Object - not everything's suitable for hashing. Instead, have an IdentityComparer which does the same thing, and keep the IComparer<T>, IComparable<T>, IEqualityComparer<T> and IEquatable<T> interfaces for custom comparisons. Poor support for immutability Poor way of discovering extension methods - it should be a much more conscious decision than just the fact that I'm using a namespace.

这些都是我想出来的，明天问我，我会想出一个不同的5个:)

PHP:

1)强迫我创造不必要的变量:

$parts = explode('|', $string);
$first = $parts[0];

2) lambdas的实现如此蹩脚，它大致相当于使用eval()，而且如此糟糕，我从未使用过它(参见http://www.php.net/create_function)。

3) try/catch系统只能捕获大约80%可能发生的错误。

4) Regex支持和lambda支持一样蹩脚，因为它必须在常规字符串中编写，这使得最难学的编程工具之一变得困难了三倍。PHP应该是一种“简单”的语言吗?

5)没有办法安全地从$_POST中取出东西，而不写两次或构建自己的函数，或使用'@'操作符:

$x = isset($_POST['foo']['bar']) ? $_POST['foo']['bar'] : null;

6)额外答案:“@”。如果你懒得写正确的代码，那就添加'@'，这对以后调试你的代码的人来说太糟糕了。

Python (3.1)

奇怪的无序T if C else F语法用于条件语句。 字节字面值看起来太像STR字面值了。我们应该得到x'414243'而不是b' abc '。 str在某些平台上是UTF-16，在其他平台上是UTF-32。(尽管至少比2要好。x字符串。) 具有相同的加法和连接运算符。这对numpy.array这样的类型很不利。 运行缓慢。

C++

Strings. They are not interoperable with platform strings, so you end up using std::vector half of the time. The copy policy (copy on write or deep copy) is not defined, so performance guarantees can not be given for straightforward syntax. Sometimes they rely on STL algorithms that are not very intuitive to use. Too many libraries roll their own which are unfortunately much more comfortable to use. Unless you have to combine them. Variety of string representations Now, this is a little bit of a platform problem - but I still hope it would have been better when a less obstinate standard string class would have been available earlier. The following string representations I use frequently: generic LPCTSTR, LPC(W)STR allocated by CoTaskMemAlloc, BSTR, _bstr _t (w)string, CString, std::vector a roll-my-own class (sigh) that adds range checking and basic operations to a (w)char * buffer of known length Build model. I am sick to death of all the time spent muddling around with who-includes-what, forward declarations, optimizing precompiled headers and includes to keep at least incremental build times bearable, etc. It was great in the eighties, but now? There are so many hurdles to packing up a piece of code so it can be reused that even moms dog gets bored listening to me. Hard to parse This makes external tools especially hard to write, and get right. And today, we C++ guys are lacking mostly in the tool chain. I love my C# reflection and delegates but I can live without them. Without great refactoring, I can't. Threading is too hard Language doesn't even recognize it (by now), and the freedoms of the compiler - while great - are to painful. Static and on-demand initialization Technically, I cheat here: this is another puzzle piece in the "wrap up code for reuse": It's a nightmare to get something initialized only when it is needed. The best solution to all other redist problems is throwing everything into headers, this problem says "neeener - you cannot".

诚然，其中许多内容超出了严格的语言范围，但在我看来，整个工具链都需要进行判断和发展。

Common Lisp:

关键词往往太啰嗦。 库支持是可怜的。 在希望更严格地处理内存的操作系统中不能很好地工作。 没有与操作系统交互的良好工具。 “循环”功能没有很好地定义，当然看起来也不像Lispy。

我是在冒险，因为我不能全职使用它，但无论如何我会尝试一下!

Perl 6

func("frew") != func ("frew") It annoys me, but there is good reason for it. In Perl 5 print (5 + 6) * 10 still gets me every now and then It may be easier to parse than Perl 5 in a lot of places, but it still kills my editor sometimes It still has a lot of the line noise Perl 5 which scares a lot of people. That means it's harder to get them excited etc. There are no libraries yet. This will be a non issue if Perl 6 does indeed end up supporting Perl 5, but that may be a burden not worth bearing. There's no REPL, or what rubyists would call irb. A solid interactive Perl 6 with tab completion, color coding, etc, would make using and learning it so much nicer. Currently the documentation is basically the English spec. Not exactly an easy read. I know it's a stupid cliche, but it's not out yet! (I am allowed to complain because I am helping :-P)

前三点是语言;剩下的并不是语言本身，而是它还没有问世的事实。