Similarly, "stupid hack" adds nothing that just "hack" doesn't say. And in that case, why have a comment at all? The code is likely obviously hacky.

At least I can have a laugh while looking at the hack someone came up with...

I contend there is a significant difference between a stupid hack, and a better one. The negative adjective is meaningful in the comment.

Meaningful, perhaps, but not at all precise enough to be understood by everyone who might read your code in the future. Many people will understand the difference between "hack" (or even "clever hack") and "stupid hack" in a variety of different ways, many of them not in the way you intended.

When I was in my 20s I would write comments like that, but now what I'm in my 40s I see them as entirely useless, aside from a way for the author to blow off steam. Code that others have to read is not the place for that.