Applicatiion to become a Good C# Developer

Question

What kind of applications you need to be able to build in order to BE an excellent C#-DEVELOPER ??
I give 2/3 examples :

  you should be able to create:
1) a Master/Detail database Application
2) a Chat Application
3) a Transaction Application where you get paid through debit-Cards......[Visa/MasterCard]  {selling products BASICALLY !}


I am sure someone has so many other applics to add to the List .........  so please GO Ahead !

I will appreciate this small effort to HELP !


Thanks.