I wouldn't say 3 was bad for my DD. Overall, she steadily got easier as she got older. The one thing I remember about 3 was that that was the age where I sometimes began to get angry at her for behavior, rather than just frustrated about the situation without blaming her for it. When she was 18 months and cried because I went upstairs for a minute without her, I didn't like it, but I didn't expect anything different from her. When she did the same thing as a 3 year old, I had a hard time being as tolerant.
Now my DS is 3, and I'm finding that he does seem to be more difficult in some ways than when he was 2 (and more difficult than DD was at the same age.) He seems more likely to freak out over small things. Sometimes when he doesn't get what he wants, he immediately starts in with yelling or crying that strikes me as way more intense than what he would have done when he was 2. Some of it may just be that now he's older I'm a little less inclined to cater to all his whims, but I don't think that's the only thing that's going on.
Now my DS is 3, and I'm finding that he does seem to be more difficult in some ways than when he was 2 (and more difficult than DD was at the same age.) He seems more likely to freak out over small things. Sometimes when he doesn't get what he wants, he immediately starts in with yelling or crying that strikes me as way more intense than what he would have done when he was 2. Some of it may just be that now he's older I'm a little less inclined to cater to all his whims, but I don't think that's the only thing that's going on.