Nerd Sniping := Getting sucked into an interesting problem at the cost of other goals you care about.
Nerd Sniping can be described in jest, as in the above XKCD comic, but is a very common problem amongst smart nerds. It's global and local. We nerd snipe ourselves when we jump to the fun, functional programming solution that takes twice as long to implement or when we choose a tech stack because it's cool and interesting rather than what delivers value fast enough.
Nerd Sniping is dangerous because it feels like the right thing in the moment. It feels productive. You're learning. Everyone thinks you're smart.
But sticking your head above the trenches looking for interesting problems to solve adds complexity, slows you down and is unkind on your teammates who will have to interpret the mess you'll inevitably end up making.