Type system terminology.

Tuples. Java and C# are incomplete without them.

compareTo(…) is bad. Java’s “compareTo” method of implementing ordering (also used by C#) is a bad idea.

Type erasure is not evil. Though the Java generics implementation kinda sucks, type erasure itself is not necessarily a bad thing.

Microsoft CLR is nice, but could have been a lot nicer.

NULL is a hack. If you program in C++, Java or C# (or one of many other languages), you’re probably performing implicit, type-unsafe casts all over the place.

Simple type inference. Something that any statically typed programming language should have.

The XML data model is broken.

Even though XML is a horrible format, you’ll still hear people using the standard set of bad pro-XML arguments.

Apple’s property list XML format is pointless.

How data should be represented (I think).

C preprocessor abuse. If you haven’t used macros for anything besides defining some constants and function wrappers, you’re missing out on a lot.

GNU Make thunks. Lazy evaulation in Makefiles.