I do not  feel lonely when I am not surrounded by friends. It is not possible and would not be good having friends  around me twenty hours each and every days. When I am alone I can think ,read, listen to music and work better. When I am with friends it is great, when I am alone it is great too. We can be alone and not lonely :).

Set goals, work hard and make progress. You won't have the time or energy to be alone. Keep only truly special people in your life and you won't get bored with the friends you have.

To be true, i've never thought about that, maybe because I don't fell alone in spite of sometimes I want to be alone for hours...!

yes there are times when we don't open up and it's necessary.

“We're born alone, we live alone, we die alone. Only through our love and friendship can we create the illusion for the moment that we're not alone.”  - Orson Welles  -