Bad Appeals to Authority

A lot of times I believe what people say and what they're arguing just because a lot of other people believe them too. A most common thing would be to believe our friends just because they sound like they know what they're talking about or when they peer pressure you into thinking something, like if someone peer pressured someone else by saying "You should smoke, everyone else is." Another example would be gossip, like when some says "Yea he's dating her, I saw them together," and then another friend would add on to that saying "Yea, I saw them together too one time." Then I would believe that friend just because my other friends believe it too. Or sometimes when I hear a smart person say something and they're totally joking around, but I believe them when they say it just because I know they're smart. Well, in evaluating premises bad appeals to authority should be avoided.