One of the main reasons I like drawing comics is to draw expressions, especially extremes... like someone being very sad/happy/afraid, or mixed emotions, like a character being angry, but in a sad way.
It feels really nice when I can capture that feeling right =^__^= (I don't always get it).
I'm never sure what the best words for sound effects are in comics. I honestly don't care for "pow" for a punch. I'm probably the only one who thinks PAF! is appropriate, but I'm sticking with it XD.... 'paf' might be a french thing.
In any case, its got a lot of 'oomph' to it.