So, we know that Asgardian's have a high tolerance to alcohol... but what about caffeine?
We know they don't have coffee on Asgard. We can assume that they have tea, though. Tea has less caffeine than coffee, 0-70 MG, depending on the brew, coffee 95-200 MG, again depends on the brew (no, I'm not counting decaf coffee, that's not coffee!).
It is simultaneously funny to think that when Thor first tried coffee, he was...
1. Completely unaffected and found out later that he should have an energy increase followed by an energy crash.
2. Completely over ran with energy and was bouncing off the walls, like most of us do after the second or third Monster of the day, before crashing and having to take a nap.
Thor drinks it because he genuinely likes the taste and thus is like me, not sensitive to bitter.
Fandral, doesn't like it at first. Until he's shown the plethora of stuff he can add to it to cut the bitter taste. He's not someone who makes a barista want to quit, just give him the white chocolate caramel one.
Hogun, while doesn't really like the taste, he starts drinking it more as he learns about Midgard Millennial culture. Hogun is the person who asks for his coffee as black as his soul. He secretly likes fueling the fact that people are a little scared of him, keeps the unwanted socializing down.
Loki, is similar to Hogun and Fandral. Loki hates bitter things (I think all Joltun's do), but saying phrases like 'I want my coffee as black as my soul.' and 'More espresso less depresso'. Similar to Fandral, but to more of an extreme, in the adding things to his coffee. Loki is the person that makes Baristas quit, the frappuccino 12 pumps of sweetener, 5 pumps of caramel, 5 pumps of chocolate, half cream, in your biggest cup.
Sif doesn't mind black coffee, she's not as excited about it as Thor, though. Sif sees it more as a way to bond with and seem more human. She usually takes hers with one cream and two sugars.
Volstagg is appalled by coffee. It doesn't matter how much cream and sugar you put into it, he doesn't like it. Things that taste that bitter must be poisonous, and no amount of trying to convince him other wise will work.
Thor also genuinely liked the drink, that doesn't change. We just have to concidered if he likes how caffine makes him feel. I'm sure he would quickly figure out that he has more energy after drinking it, but might not know why. Someone would have to explain it to him. While I don't think Thor would be an annoyance with one good cup of coffee. I think after two or three, he would get hella hyper and probably bounce off the walls. Because of this, I think Thor would be careful about how much and when he consumes coffee. He'd probably have a cup in the morning with the others, and that's it.
Fandral, still has to have all the cream, sugar, and extracts, in his coffee. HOWEVER, this guy has the ADHD and gets a different reaction to the drink than the others. The world is now clear for him, his thoughts are slower, he can remember tasks he was told to do... he's well, kinda 'normal', and he kinda hates it. Imagin having ADHD for a thousand years and then suddenly you're kinda 'normal'. It would confuse the hell out of you, and it confuses the hell out of Fandral. Though, he would use it to his advantage; gotta go to a SHEILD meeting? Cup or two of coffee. Got a long time consuming task that requires all attention? Coffee. I do think he would look for an answer to this. IDK who would give it to him, Bruce, he's a chemist, right? Or Stephen. I don't think this would immediately raise SHEILD's suspicion of Fandral having ADHD, but at some point, he does get tested.
Loki, still hates coffee, until he learns about the energy boost he can get from it. This would be the only way Loki would ever condition himself to liking black coffee. He would still say the funny Millennial sayings around coffee... he probably gets really engrossed in coffee culture and becomes a coffee snob.
Volstagg, after learning that it gives an energy boost, still won't touch it. Though he's more understanding of why people consume it.
Sif and Hogun, nothing changes. Go back to 1. It's the same. Sif drinks coffee to seem more human, caffine be damned. Hogun just avoids it at night.
((Edit- I forgor Hogun on part 2....))