I was gluing up a stool the other day. My drilling was accurate, all my holes lined up. I cooked the dowels in my reading lamp/ coffee can kiln so they were just a bit undersized and went into their holes easily. I glued on the seat and that went well. It banged right down onto the legs and the clamps pulled it down tight the rest of the way.
The leg dowels were sticking up maybe 1/2″ over the surface of the seat. No worries. I had made the wedges thin enough at their starting end to enter the narrow wedge slot easily. I started one in straight, the sound was good when I got to the bottom and I made one more little swing of the hammer.
Bang, I busted off half the dowel sticking up from the seat. Only it also broke off 1/8″ under the surface of the seat. One blow of the hammer and now I was working to find the fix for it.
The simple thing would have been to saw off the excess dowel so there wasn’t so much above the seat. Simple decisions like that can change your afternoon.