What is wrong with going to Yankee Stadium to watch ballgames?
It states “ve’lo seilchu be’chukas ha’goy” – you shouldn’t walk in the ways and customs of the nations. The Rambam states in Hilchos Avodah Zara that you shouldn’t follow the practices of goyim. Not because it’s a certain practice that is wrong and should not be followed but because we should be different from the gentiles in the way we enjoy, in the way we behave, even in the way we clothe ourselves, the Rambam says. Otherwise, if you participate in the things that goyim do, your mind and your dei’os, which means your character traits, will begin to imitate the nations with whom you are associating.
Now, let’s say you sit down at a ballgame. All of sudden, the pitcher throws the ball and the man at the base gives a whack with the bat and everybody goes crazy: “Whoooo!” They’re shouting. They stamp their feet and he’s running and you are ignited. Your blood becomes ignited by the excitement, which means you are participating in the hevlei hagoyim [emptiness of the gentiles]. To be excited over nothing is avodah zarah.
When Moshe Rabeinu came down from Har Sinai, he said, “What’s this kol [sound]?” “Ein Kol Anos Gevurah” – it’s not the sound of people shouting thanks to Hashem because they’re winning a victory. That I could understand, to shout out to Hashem because of gevurah -you’re winning a victory. “V’ein kol anos chalushah” – it is not the sound of crying out in weakness. If a person is afraid of losing a battle, he cries out to Hashem for help. So crying out to Hashem in happiness or in entreaty, bakoshoh, I understand. But, “kol anos anochi sho’mayah” – just a voice of making noise for nothing! A noise for nothing, that’s avodah zarah, to get excited over nothing. We have to be excited over only one thing in this world: “halelee nafshi es Hashem” – my soul becomes excited only about Hashem. And when you’re sitting at a ballgame and you go wild over a ball, over a pitcher, over a bat, then you have to know that this is really sinking your mind into the mire of avodah zarah, and you’re beginning to lose all the segulos, all the precious attributes of the Jewish mind. In order to preserve our mind, our emunah, our attitudes, our understanding and our dei’os – dei’os means the middos of character, our reactions – it’s important to remain separate from the goyim.
By the way, it’s important to keep separate from wicked Jews too. Not only wicked Jews, even Orthodox Jews who are fools. There are plenty of fools by the Orthodox too, oh yes. You have to be careful with whom you sit with in a beis ha’knesses. A fool sitting next to you can be speaking loshon harah or leitzanus during the davening. You have to be careful. The Rambam says “derech bi’ri’yaso shel ha’adam li’hiyos nimshach bi’dei’osov u’bima’asav u’bidrochov achar rei’uv ve’chaveirov.” A person is drawn in the way he thinks and the way he behaves according to with whom he associates. So even among fellow Jews, you have to be careful. But to associate with gentiles is a special lav of the Torah. Hashem is saying, that as much as possible, you should avoid the things that gentiles do because once you start doing the things that they do, even though it seems harmless, you should know that in all other areas your mind will begin to work like a gentile mind.