Keeping a beer cold is what helps a beer stay fresher longer, but it’s a pervasive myth that if you allow a cold beer to become warm, something bad will happen to it. The most common misconception is that if a cold beer becomes warm, and then is cooled down again, it will skunk, but skunking comes from lightstrike, not temperature fluctuations.
If you’ve just accepted a fresh beer delivery from your local shop or brewery, but don’t seem to have enough space in the fridge (trust me, I’ve been there), don’t worry about needing to make room right away. The beer will be fine if you leave it at room temperature in your home. In other words, not in a hot garage, or out on the deck in the hot sun, unless it’s winter (and not freezing out). That type of extreme heat — think 80-plus degrees — will, in fact, ruin the beer.
Then, when you’re ready, put the beer in the fridge, cool it back down to your ideal temperature, and enjoy. The flavors should be just fine.