My old method was to cut a circle into the core end around the core and then pull out the core - typically leaving lots of seeds inside the pepper. Those seeds would get more widely distributed as I proceeded to cut up the rest of the pepper.

The method my wife taught me is to start cutting on the other end and make multiple parallel cross sections until I get to the core. The pepper now resembles a cup with a core in the middle. At that point I alter the direction of slicing and cut off the sides of the cup, leaving only the core. The advantages of this method are that a) I can clearly see the core when I am cutting around it, so I don't accidentally cut into it and b) I don't have to pull the core through a hole that tends to be too small for it.

I'm sure there are multiple non-stupid ways to slice a pepper. I'm quite bad at what we could call 3D reality manipulation and have to be explicitly taught obvious things. My father (also an engineer) is the same way.