Most are, even in cafes. I didn't realize this at first, and I bought an espresso machine to be more convenient than starbucks. But, it took me at least 2 months of owning an espresso machine before I was able to get the grind, tamp, extraction temperature and extraction time right to pull a good shot consistently. Honestly, it was two months of pain. But, it's been heaven ever since.
I don't mean to be a snob about it, but I used to enjoy starbucks espresso drinks -- not as much anymore. They're slightly bitter or sour most of the time, and once in awhile they're completely undrinkable. I live between two starbucks and I travel a lot, so it's not like it's just one bad location. I still go to starbucks once in awhile, but only if it's for a social reason... not for the coffee. My wife was not convinced at first, but now she agrees that my lattes are better and more consistent than Starbucks.
I think anyone who likes coffee will have the same reaction as you... their mind will be blown when they have a proper shot of espresso and they will probably hate it until that time. So, if you enjoyed it more than coffee, you could take the plunge too. It's like a lot of things though, if you want to do it right you often have to do it yourself.
I started delving into espresso and it is both immensely frustrating and immensely rewarding. It's really hard to pull a good shot. But once you do you can't go back.
Some beans are very forgiving and give a decent espresso with a wide range of parameters. Some beans are very picky on getting the settings right.
I've had a range of machines - and my current machine is the only one that I can get a decent cup from (BES920).
To your question, you need to adjust depending on the output from your machine.
I daresay that espresso is a very different style of coffee for people who are used to immersion brews. Espresso drinkers would prefer what they're used to. To each their own.
Most espresso shots end up being sour and unpleasant for me, but I've had a few (most recently, at Pablo & Rusty's in Sydney) that absolutely blew my mind.