What Are the Three Tritest Tropes in Titles?

Since reading The Elements of Eloquence, I am seeing tropes everywhere. Unfortunately, most people seem to go for the low-hanging fruit (Boo, badly overused metaphor!), especially in the titles of blog posts.

Numbered lists are probably the most common, for three reasons:

1. Someone did some research once and found that they lead to more click-throughs, so there’s at least a pseudo-scientific basis for this one.
2. They give the impression of completeness.
3. They promise a quick and easy read.

Alliteration is a cheap way to win one’s attention. It’s easy, and personally pleasing to peoples’ ears, even when it results in rotten writing.

Why do rhetorical questions get our attention? Is it because they spark curiosity? Do they exploit our continuous search for meaning in a chaotic world? Who knows?