One of the suboptimal techniques that developers often use, is a query that retrieves the entire content of a table, without any conditions or filters.
For example:

SELECT * FROM table_name ORDER BY column_name;

This is acceptable if there are not too many rows in the table, and there is only one call per page view to that function.
However, things start to get out of control when developers do not take into account the frequency of these calls.
Here is an example to illustrate the problem:

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