Why did Germanic tribes seem to be more effective at fighting the Romans than other barbarians like Dacians, British tribes, and the Celtic Tribes of Gaul? Did Germanic peoples have better weapons or tactics?

The Dacians won several fights before the Romans won.

According to history the Romans tried fighting the Germans a few times and lots but ultimately lost interest because there wasn't alot of treasures to be looted.

Dacia was famous for it's riches at the time and the Romans brought home large amounts of gold and silver.

Dacia was of more interest to the Romans.