Learning a foreign language takes time and dedication. The reasons below may help to convince you to take the plunge, if such persuasion is needed. Some reasons are practical, some aspirational, some intellectual and others sentimental, but whatever your reasons, having a clear idea of why you're learning a language can help to motivate you in your studies.

When you move to a different country or region, learning the local language will help you to communicate and integrate with the local community. Even if many of the locals speak your language, for example if your L1 is English and you move to the Netherlands, it's still worth your while learning the local language. Doing so will demonstrate your interest in and commitment to the new country.
If your work involves regular contact with speakers of foreign languages, being able to talk to them in their own languages will help you to communicate with them. It may also help you to make sales and to negotiate and secure contracts. Knowledge of foreign languages may also increase your chances of finding a new job, getting a promotion or a transfer overseas, or of going on foreign business trips.