If you own a restaurant/bar, you get the benefit of not having to pay your tipped employees a living wage and in most cases, health care or any other benefits. You get to pay minimum wage and still have employees that give a shit. That's a wonderful thing for a business owner. You can rely on your customers to not only pay your bills, but also your employees'.
So when you order a shit ton of food and/or drinks for you and your friends from your own place for free, TIP YOUR FUCKING EMPLOYEES! They are LOSING money when you don't. Your order(s) take time to make/prepare. That means that other PAYING customers have to wait longer and fair or not, that affects what they tip your employees. So now your employees are doing extra work for you for FREE and losing money from the people they are supposed to be taking care of. Seriously, your friends would have been happy to pay their tab(s) and TIP. So there's more money your employees are losing out on.
I know it's cool that you have your own bar and you can take care of your friends there, but it's also cool to take care of your people. You know, the ones that make that bar function, because you don't. If you just saved yourself and your pals $70, would it really hurt to throw the staff a 20 spot? And you wonder why we steal shit?