Never Resign! I don't even know what a Zugzwang is
After blundering a piece for free, it's easy to just say 'there's no way I can win' and resign. However, I would suggest to every beginner (and even intermediate players) to play every game out until one player is checkmated or the game is drawn. There are several reasons to see a bad game to the end, the least of which is in the hopes of a miraculous win or draw.
I believe the first and foremost reason to never resign is, you'll never panic again. The moment you start thinking your game is hopeless, it becomes hopeless. I was once in a complicated closed position where both my opponent and I were racing to mate the other opponent's king first.
Keep your cool in tough situations, and you may find hidden resources.
The next reason to never resign is practicing practical defense. In tournaments, you may not always have the luxury of losing. Playing a game out to the end will help you recognize defensive patterns to help you survive in tough situations. You may find that after trading key pieces, you can develop a stronghold to hold the game. This is not something that anyone can foresee 15 moves back, so practice your practical defense!
There will also be times where you will have a bad piece or be under developed. These situations can feel like you're down a piece or two, and you'll need to know how to weather the storm until you can call in the calvary or liberate the bad piece.
Another reason to never resign is you'll get to see how to crack other's defenses who are stubornly trying to defend the position. Never doubt that your opponent will do everything he can to win or draw the game. With this being said, your opponent will be attempting to crack your defense, and you may learn a few tactics the next time YOU are up material. It may be a tought loss to swallow, but remember that we often learn more from our losses than our wins.
The last reason never to resign is, you never know what can happen. If you are experienced in practical defense, you'll find the most accurate moves faster. This may cause your opponent to come under time pressure and perhaps blunder as well. They may have a moment of chess blindness and drop a piece, putting you back in an equal position and back in the fight for a win.
Learn from your mistakes, and learn how your opponent exploits them. There is no better teacher than experience, Never Resign!
CJ aka Bloodbeard