Why is it that eating and drinking in large groups is the preferred way for most to celebrate things?

That is the worst of all worlds to me, anyway. My wife is finally getting this. Last Father’s Day, I went to the ball game alone. I sat in my seat, with my name on it (yes, it really does have my name on it) that is generally away from where the crowd likes to sit. I sat there, alone, and watched the boys do their thing. I went home, and there was a note saying that my gift is her and my daughter were staying the night at my wife’s moms house so I could have the evening alone. BEST CELEBRATION EVER!!!! Not saying my way is right and group parties are wrong, but I just never understood that. Especially those who like to do stuff like that with complete strangers, like on dinner cruises or community dance parties. (This coming from a guy who spent 10 years or so in a polka band playing many of these community dances). Any insight would be nice, as it is more of a curious thing, not a “judgemental, YOU’RE ALL WRONG” thing.