Here’s why: there are way too many variables that can influence your experience. Your mood, the temperature, your friends (or lack there of), the bouncer, the bartender and most importantly the beer.
Keep in mind that microbreweries are great because they have the chance to experiment with techniques and ingredients MUCH MORE than the big guys. This means that it is also much more likely that they will create something less than fabulous every now and then. Out of 10 beers on the menu, 9 of them may be outstanding but you happen to choose the one that was less than great. One beer does not a good brewery make!
My advice is to try more than one beer and in more than one style. It’s entirely possible that it’s the first time the brewer has attempted a coffee stout but he specializes in a strong ale and you may have missed out on the opportunity to sample it. Worst case scenario, you tell people to stay away from an otherwise amazing place to go. I like to withhold judgement until I have soaked it all in.
Remember that the many things that make a microbrewery great may is also a reason why you need to be more open and understanding. We can’t have one without the other and that’s a trade-off that I am more than willing to make. Go out there and have an open mind and enjoy everything that craft beer has to what offer. Always sample more than one beer from a brewery.