In the age-old debate about seat reclining, everyone is right, and everyone is wrong. However, the most wrong are the people who choose to be obnoxious about it.
As with everything in life, being courteous should always come first. Don't make someone else's life worse just because you can — whether you're pro- or anti-reclining. We all just want to be comfy, so let's meet in the middle and be nice to each other.