Tom Christiansen's Csh Programming Considered Harmful used to be posted to various Usenet comp.unix groups, nigh on ten years ago or so. I consider it sort of a pity that it isn't still being posted, because every so often someone still decides that writing shell scripts in csh would be a good idea.

Some of the problems Christiansen identified have since been fixed by modern versions of tcsh, but not all of them.

(The article can also serve as an interesting catalog of sh programming tricks.)