Treat your server like a human being with a brain
It’s a sad reality that a surprising number of customers assume servers are doing their job because they’ve somehow failed in life. This isn’t an issue unique to servers -- people do this to employees at virtually any food-service or retail-adjacent job. The thing about serving in particular, though, is that it’s the single job that offers the greatest amount of free time for someone to pursue other work, like, say, acting, writing, music, or really any other creative gig. Still, others choose to wait tables when they could be doing something else -- I don’t understand these people any more than I understand astrophysics, but I’ve known more than a few human beings who were smart people who legitimately chose to do this for a living. The point is: Don’t assume your server is a server because they’re dumb -- just because you work in a damn office building doesn’t make you smarter than them.
Be aware of your server's time constraints
Sometimes we really like talking to customers and just shooting the shit; if we’re lucky, we’ll establish a rapport and they’ll wind up becoming regulars who will tip us well and ask for us every time they come in. But this comes with a caveat: Be aware of the situation around you. If the place is empty, the server has plenty of time to hang out with you. If it’s packed, they’re not going to have time to listen to you talk about your damn screenplay, KEVIN. Just try to make our job as easy as possible -- trust me, we notice and appreciate it.
Be willing to forgive a mistake
Mistakes happen. Be a human being for five minutes and understand that simple fact. First, as long as the server immediately works to correct the issue, if you’re going to hold it against them and hold their income hostage to one simple goof-up, you’re an asshole. Second, you have no way of knowing whether the mistake was the server’s or the kitchen’s -- it really could easily be either in the vast majority of situations. Don’t be the dick-knocker who uses any mistake to prop up your smug sense of superiority -- forgive it and move on.
If there's an issue that can easily be fixed, point it out when it can be fixed
This might seem confusing, but most servers who are good at their jobs don’t have a “just shut up and eat it no matter how unhappy you are” mentality when it comes to customers. We WANT tables to be happy, because happy tables give us more money and allow us to pay for more illegal narcotics that we might use to forget the fact we’re waiting tables. But don’t wait until the very end of the meal to mention it if there’s an issue -- if your steak isn’t cooked the way you ordered it, tell us so we can actually fix it. Finding that out at the end of the meal is just frustrating for us.