Forget doesn't work

You did a small mistake, actually you didn't notice that. I did myself :).

Forget use the array key to delete an object item from collection.

Array(0 => 'abc'
 1 => 'bcd'
 49 => 'aaa'
)

$examples->forget(49);
                  ^^ array key 49

Where as, find use the id to find an object from an collection

table: examples

id example
1   abc
49  bce

$examples->find(49);
                ^^ `example id`

I just wanted to add on to the Anam's answer. Once you have a collection you can then loop through it like this to delete by ID

function forgetById($collection,$id){
    foreach($collection as $key => $item){
        if($item->id == $id){
            $collection->forget($key);
            break;
        }
    }
    return $collection;
}

$examples = Example::where('example', '=', $data['example'])->get();

$examples = forgetById($examples,20);