Possible Clues:

• "What a surprise to run into you!"
• 'Hey, didn't see you there ...'
• “When’d you come in?”
• 'I didn't see you there!'
• 'Didn't expect to find you here!'
• ''Didn't expect to see you!''
• 'Didn't see you there ...'
• 'What a coincidence to run into you!'
• 'Surprising to run into you here'
• "Well, howdy"