Non c'è problema. Tutti sono stati nuovi inizialmente.
Ti riporto di seguito la definizione di Side Effect da php-fig PSR-1:
The phrase "side effects" means execution of logic not directly related to declaring classes, functions, constants, etc., merely from including the file.
"Side effects" include but are not limited to: generating output, explicit use of require or include, connecting to external services, modifying ini settings, emitting errors or exceptions, modifying global or static variables, reading from or writing to a file, and so on.