I was surprised to discover a friend of mine kept her butter out, but she swore she’d never seen it go bad, ever. So I tried it and… it works.
I keep it on a dish under cover, and it can stay like that for weeks and never go bad.
This solves so many problems!
Garlic press.
Yes, I keep the butter at room temperature, but the other sticks are in the fridge and I’m the only one in the house who grasps the concept that when stick A is more than half finished, it’s time to pull stick B out of the fridge…
I keep my butter on the counter, but every once in a while I’m faced with a “fresh out of the fridge” stick of butter. I take a table knife and pull it along the top of the stick of butter to make nice, soft butter curls. Works like a charm.
ETA: No matter how hard I try, I can never hit that sweet spot with microwaving. My stick of butter either emerges unaffected or in a puddle.
+1. This technique is also known as “butter planing”.
We just buy soft butter (mixed with canola oil) in a tub. It spreads straight from the fridge.
Same here. I usually have butter on the counter, but sometimes forget. This works perfectly.
The problem with microwaving butter is that the sticks melt from the inside out. 2 seconds can make the difference between butter that is still too hard to spread on the outside of the stick and a puddle of melted butter in your microwave.
I am amused by the juxtaposition. 
The kind of kitchen that’s in a climate-controlled house. What kind of home do you have that gets hotter than 85F without someone clicking on the AC? 
I never knew it had a name. I usually don’t end up with curls, but with a work-warmed blob of butter after multiple knife passes.
I remember that Grandma’s refrigerator used to have a butter safe in the door with a dial that let you choose how cold, and therefore how hard, the butter would be kept. I’m guessing that having a warmer inside a refrigerator went out with the first energy crunch.
DCnDC has the right answer: microwave one pat of butter on a small plate, then dip the bread in it.
We keep our butter out on the counter, but in the wintertime we let the house go down to the low 60s at night and the butter is hard in the mornings. Thus, melt and dip.
Unless you happen to find the notion of melted butter on bread kind of revolting. No offense, and I loves me some garlic bread and the like at dinnertime with flavored butters melted into the heated bread slices, but for a hunk of bread at breakfast, no.
Smooshy soft spread butter yum, oily drippy melted butter yuck. (And yeah, I know that chemically speaking there’s hardly any difference between them, but that’s not the point.)
So what is the critical ambient temperature at which you should start to worry about leaving butter out? I’m in a house that typically gets up into the 90s in the kitchen.
nm
We keep it on the counter as well. My only problem is that sometimes in the summer the butter gets too soft. We’ve never had it go bad, though.
ETA:
For us it is the point that the butter becomes so soft it starts losing its shape on the butter dish.
Winter time I keep butter in the cupboard on the north wall of my house. It is about 5 degree cooler in there than the house.
Summer, I divide the sticks of butter into portions that I want and take out of fridge as necessary. Butter is usually gone within a day.
I don’t go through a pound of butter very quickly, unless I bake with it, but I leave most of it in the fridge and small amount out (where the dogs can’t get to it) so it’s not rock hard when I want some.
If I do forget to have butter out, I take the knife and scrape it quickly across the top of the butter a bunch of times and that seems to collect enough soft butter to spread. Not quite butter curls, but similar.
It has to be ten seconds exactly or that’s what happens. I’ve been distracted several times and ended up with a large puddle to clean up.
Why don’t you just set the timer for ten seconds? 
Dang - you like it hot! I’d imagine the answer to your question varies by how fast you go through the stuff. If you’re finishing a stick every couple of days, I imagine it’d be fine.
Nearly everyone I know in the US uses salted butter for spreading, but just for the record: salted butter doesn’t go bad nearly as fast as unsalted butter. The butter is there for both flavor AND preservation.
This isn’t all that out-there, really. Actually, I get the butter on the bread (one way or another), then nuke it 15 seconds. So working with ceramic-tile bread and brick-hard butter is plausible. May need a chisel to separate the frozen slices? I’m picturing running the brick-hard butter through a pepper grinder 
SO, I’m seeing a broad consensus here for simply leaving the butter out in the wilds of the kitchen counter. If that really works just fine, sounds like the simplest solution of all. Note, I use the unsalted type, which someone above mentioned, tends to spoil faster. I’ve dabbled with some of your other suggestions above from time to time – like shaving “curls” off the top of the brick, etc.
I think the ideas here that I will try next (including some of my own, and others) might be:
– Freeze butter to make it harder, thus more grateable.
– Refrigerate the grater so butter won’t soften so fast while I grate it.
– OTOH, just keep butter out. If it doesn’t spoil, this is easiest of all.