This question is hard to give a specific answer to. A variety of issues impact the question.
One of the main reasons a person can seem "sickly" is that they may have some sort of reduced immune system function which causes the person to get sick easier and stay sick longer. Their body may not be able to fight of germs and other organisms as well.
Another reason some people may seem more sickly is that they do not handle sickness that well. While one person may function rather normally even when suffering from a cold, another person may want to stay in bed all day. Neither of these people is necessarily wrong; they just have different personalities. (It should be noted that people that stay home and in bed even when they have rather slight illness, such as a cold, are actually probably doing more good for others, as they are not spreading illness. While they may be viewed as "weak" or "wimpy," they are actually doing what they should and isolating themselves.)
A third reason people can seem so sickly is because they may not get proper nutrition to allow their body to function properly. This is closely related to immune system disorders. Those in "third-world" countries may suffer from this type of lessened nutrition.
Other reasons certainly exist, but these are probably the most discussed ones.
Many mundane things seem amazing to some Americans.
not exactly but some peoples genetics are really good so that it may seem so
Some people seem to think so!
not really. some people may seem nice, but are jerks, and some people may seem like jerks or weirdos abd are really nice. i learned this the hard way, so put your guard up if the person may seem a little bit mean.
Jana Duggar's reserved style may seem distant to some people, but remember: Still waters run deep!
Traditions that may seem strange to you obviously aren't strange to those people who hold them dear. To some people, the idea of saluting the national flag every day might seem strange, it's not done in every country.
I have seen some Time Trial times that are so fast they seem impossible.
There are few, if any people, who do not know about these laws. It may seem as though some do not, as they are willing to challenge these laws in court so they ignore them.
Some shallow people seem to think so. I know very rich people that drive inexpensive cars. Probably one of the reasons they are rich.
some seem to think so. It makes for some interesting stories.
Zombies do not exist so there will never be an apocalypse. Some people go through life zombie like and never seem to catch on to life.
It would seem so