There are a lot of reasons why it can make sense to go with the majority. Going with the popular view is a shortcut for taking the time and effort to make our own decisions from scratch. We might reason that if others believe it, then it's probably true. But we can also keenly feel the desire to conform to the majority view because it's uncomfortable to hold a different opinion — the easy choice is so often to go with the flow even if, deep down, you disagree. So we get the bandwagon effect.
The bandwagon effect can lead to the Abilene paradox — where a group can make a decision that no one in the group agrees with. On a night out it may lead to just following the crowd, but in a company it could lead to launching a product that no one thinks is good or, more seriously, in safety critical industries like airlines, if people don't feel comfortable speaking up against the group or authority it could lead to accidents.