It's a matter of taste to a certain extent, but panel three really doesn't make sense. It doesn't match up with how anyone would naturally vocally emphasize that sentence and it doesn't highlight any important meaning either. If you emphasize too many words in a sentence, you get a similar effect to audio compression causing a loss of dynamic range. Humans experience stimulation by contrast: if everything is emphasized, nothing is.
It's also worth noting that italicized text is often a better choice for this kind of emphasis. In any case, the visual noise makes it difficult to read past a certain point.