I grew up with the mistaken notion that the colder the brew at serving the better it will taste.
I recently brewed a porter and added a substantial amount of coffee at bottling. The sample from the bottling bucket tasted good. After the beer was carbonated and chilled in the fridge and served in an ice-cold mug the coffee flavor was very bitter. In fact, I didn't look forward to drinking more of it.
When I only had a sip left in the mug, I was interrupted for a few minutes. When I went back and had that last sip (which had warmed up appreciably since there was only a small volume of beer in the mug) it tasted much better.
Now I'm much happier with the taste and have learned a good lesson.
I know, I know. I've read elsewhere that it tastes better a bit warmer, but I'm a guy that has to learn most things the hard way.