I have had a huge sweet tooth my whole life but I find the thing that I crave the most is fruit (I know fruit is sweet but not like ice-cream and candy). I've always ate a ton of apples and now that I can't I am craving them like crazy. Also, no bread is really hard, especially since good whole wheat bread seems so healthy and is so satisfying, and it limits your options for most meals like pizza and sandwiches.
I hear a lot of knee-jerk reactions about the diet saying how it must be awesome to just eat steak, chicken, etc. all the time, but it gets real old real fast. Without bread/buns, bbq source, and common high carb toppings, it become really repetitive. Cheeseburgers are amazing but they are a hell of a lot less appealing with no bun, onions, tomato, or ketchup.
All this being said I do not see keto or whatever you want to call it as a long term diet/lifestyle for me. I have been convinced that I used to eat way too many carbs, but I think I just need to balance my meals more and do some portion control. Eating no more than like 20 carbs a day is really hard and for me it affects the quality of my life too much. But, I totally understand that there are people out there where this diet is basically the only thing that works for them, so I think it's awesome that more people are at least trying it.