Could be the way your tastebuds are tuned - it's the reason why some beer can taste differently depending on the pub even though it's the same brand. Beers is often stored at slightly different temperatures, and even 0.1 of a degree can make a big difference to the way our tongues interpret taste.
beer also tastes different according the shape of the glass it's served in, it's the little bubbles, different shape glasses cause different amounts of bubbles to form, when CO2 bubbles come out of a liquid the acidity of the beer is decreased, more bubbles, sweeter beer
Same goes for the way the glasses are cleaned - any soap residue prevents the bubbles from forming properly and makes the beer go flat quickly. A good way to tell is if you get the rings (or lace) around the glass every time you drink - if they're present it means the glass has been cleaned properly. If they don't then likely there's the slightly bit of soap left over.
I feel the same. Also a very cold drink is nicer than just a cold one. Crisper. I suppose the extra hot element adds a kind of sharpness too now that I think about it.