Some friends are only meant to be temporary. Now that doesn't mean they weren't real. The time, the laughs, the memories- they were all real!
Some friends blow in with the wind and stay for a while. All you can do is laugh, help each other grow, and then let them go at the next tide when a new wind comes for them.
Don't hold them back like birds in a cage. Release them! Would you want a friend to ensnare you and with an iron grasp, hold you selfishly enraged?
Some friends are temporary, but the happiness they bring can last forever in your memories.