I don't think it's reliable to judge a person by the first glance.
Firstly, appearance doesn't represent all. The information of a person you can get from a glance is very limited. You can't tell many things just from the appearance, such as the past, hobbies, eating habits and so on. Furthermore, appearance lies, it may trick you. What you can get is partial, which may even lead to prejudice. A person who dresses decently and talks sincerely doesn't imply that he's definitely innocent and kind. You can't judge a book by its cover. So I support that one shouldn't judge a person just from the appearance.

我认为不能依靠第一印象来判断一个人。
首先,外表并不代表一切。 你从外表得到一个人的信息是非常有限的。 单从外表你无法得到很多信息,比如过去,爱好,饮食习惯等等。 此外,外观也有可能撒谎,欺骗你。 你得到的只是片面性的,甚至可能导致偏见。 一个衣着体面，谈吐真诚的人并不意味着他就一定是无辜善良的。 就像你不能通过封面来判断一本书一样。 所以我支持不应该只从外表来判断一个人。