There is a lot that could be said about bad rhymes, and many examples we could nominate, each according to our taste, but one thing that makes bad rhymes bad is that they call attention to themselves; their conspicuousness breaks the spell of the poem or song. Rather than serve it, they subvert it.
Rhymes call negative attention to themselves when they feel forced or contrived, like the poet is being pushed around by the rhyme scheme. Poets and lyricists rightly sense that they MUST follow the rhyme (in a rhyming piece), or else it will unravel, but following it to the exclusion of good sense and artistic truth leads to the ludicrous word choices we recognize as bad rhymes.
A particularly egregious example of this can be found in a song by the band, Train. Let’s look at the whole lyric, then break it down:
"Hey soul sister
Ain’t that Mister Mister
On the radio, stereo,
The way you move ain’t fair, you know."
–Train, "Hey Soul Sister"
1. "Hey soul sister…" So far, not bad, but things go wrong pretty quickly.
2. "Ain’t that Mister Mister"
Are you fucking kidding me? Are you seriously talking about some bullshit band from the 80s right now? This is the line that clearly was chosen for the sole reason that the word "mister" rhymes with "sister." It’s been said that "Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep." It’s not good to be too critical during the creative, composing phase, but for God’s sake, this is a line that never should have escaped the notebook or rehersal room. There are many factors that can make a line great, bad, or in-between. Sometimes a line tries to do too much. This is an example of a line, or a writer, doing too little. Lazy writing says, ‘It rhymes; that’s enough." But a line doesn’t just have to rhyme. It has to make sense; it has to work on its own; it has to fit the tone of the piece; it has to ring true in some way; it has to have the natural rhythms of speech, or the novelty of fresh language; it has to not-be-about-some-ridiculous-80s-band-just-because-it-rhymes.
3. "On the radio," This line only exists to try to make some sense out the previous line, which only exists because "sister" rhymes with "mister."
4. "Stereo," Was it a stereo or a radio, or both? Is this necessary? Does this really make sense, or does "stereo" just kind of fit sonically and syllabically with "radio"?
5. "The way you move ain’t fair, you know." "Stereo and "fair you know" is par for the course as pop rhymes go; not terrible, but we never should have gotten here. This whole rhyme scheme emerged as a pointless effort to cover the tracks left by the ungodly, "Ain’t that Mister Mister." In this case, the bad rhyme set off a cascade of misfortunes.
Of course it’s easy to pick on Train. (Later in this song they sing, "I’m so obsessed / My heart is bound to beat right out my untrimmed chest." Untrimmed? Seriously?) But the larger point is to learn from bad rhymes the principles that make a rhyme work.
As stated above, it should never feel like the writer is reaching too far for the rhyme. A rhyme should have the simple ease of Keith Richards warbling, "Hey baby, what’s in your eyes? / I see them flashing / like airplane lights," or the novelty of Beyonce rhyming "woke up in the kitchen" with "how the hell did this shit even happen."
Rhymes should feel natural and fresh at the same time; not forced or ludicrous, as with "bad" rhymes, but suprising and satisfying. Trying to reach the hearts of the reader or listener with bad rhymes is like sending a WWE wrestler to do the work of a ninja. Only great (or good) rhymes have the stealth and grace to deliver the Five-Point-Palm Exploding-Heart-Technique of poetic satisfaction.