Because when I happen to leave the application brush unwashed for an hour, it's still usable, whereas when I yesterday glued a piece of timber in place it started almost immediately to "grab".
In another situation I drilled a hole for a dowel through both pieces of wood, glued the dowel and hammered it in. But stupidly I had not previously located a suitable punch to punch it right through into the second piece, and by the time I did find one (30 seconds) that dowel was immovable. I've done this before and it works fine as long as one does not pause even for a second whilst hammering it through.
This is Evo-Stik Weatherproof Wood Adhesive, by the way.
I fill the hole in the outer piece with another dowel cut off flush, then planed or sanded, by the way(2).
MM