http://www.washingtonpost.com/business/capitalbusiness/darden-advice-to-the-summer-intern--making-a-graceful-exit/2013/07/26/7e7fb7ca-f2ee-11e2-8505-bf6f231e77b4_story.html
I have reprinted four of Dean Brunner's points below that address students who didn't get full-time offers from an internship. Of course, such situations also offer many benefits too!
2. Take the high road . Don’t weep, pout, plead or bargain aggressively. Under no circumstances should you slam the door on the way out. To the extent you can, make a lap around the business from the executives to your supervisor, to your peers and the administrative assistants: “Thank you for the opportunity to work with you. I wish it had worked out. Perhaps our paths will cross again. I’d be glad to stay in touch. And best of luck to you going forward.” A gift of a box of cookies or chocolates for that co-worker who made an extra effort to help you is a grand gesture. The high road exit expresses grace, dignity and self-confidence. If you stay in the same industry, you may well run into your co-workers again. The high road exit actually gives you a “bridge” with which to resume a conversation. And occasionally, the high road prompts a reversal: Weeks later you may get a call, “Um … we’ve changed our mind. Would you work for us?”
3. Get perspective. Talk through the experience with a mentor, your partner or wise friends. The key questions should be: “What happened?” “Why did that job matter to you?” “What can you learn from this?” and “What’s next?” A coach or career counselor can lend even more structure to the reflective process. Getting perspective is important for your peace of mind. And it may help you to answer questions from friends and other employers about why you didn’t get an offer from your internship.
4. Find acceptance: It is what it is. Move on. Later, you may well conclude that it was a blessing in disguise. And never forget that your worth is infinitely greater than any offer, job title or paycheck.