Sports persons and officials are human beings like all normal humans. Likewise, they are prone to faults and errors. Just like batsmen and bowlers can make silly or funny errors, sometimes, the match officials can have their bad days too.
It is not rare that we see on-field umpires making misjudgments. Sometimes those errors and misjudgments are big and sometimes they are small. A wrong decision or misread by any on-field umpire can cause massive controversy especially if the two teams involved are in a crunch battle.
Umpires are exceptionally trained professionals with incredible focusing power. But at the end of the day, they are human beings and can make mistakes of their own. There are basically four main officials in a cricket match, the two on-field umpires, the third umpire and the match referee.
The two on-field umpires are more likely to make errors and mistakes than the third umpire and the match referee. The third umpire is consulted by the on-field umpires in the case of a slow motion replay or a close call which is otherwise hard to predict by the naked eye. A 3rd umpire has access to computers and technology to aid him in making the right call, and it is highly unlikely that an error shall be made in any decision.
But no matter how safe a particular job is, every official has his bad and funny days. Watch this funny clip from a KFC Big Bash League encounter between the Adelaide Strikers and the Perth Scorchers. The on-field umpire sends a stump appeal over to the third umpire. The batsmen looks clearly out by the looks of the replay, but the screen lightens up saying “not out”, much to the amazement and cheers of the crowd and everybody at the ground.