[utku_karatas2]

In addition to that, parent's advice is also crucial for the team's motivation.

If the project is boring and you choose a boring tech stack to go, the team morale will only be harder to keep up as the time flies by.

[kyriakos]

This is probably the most important reason. Programmers love challenges. Keeping it interesting/challenging will also keep your good developers from looking for other jobs.