Historical clue formulations

• Not willing to share — 2021-11-30
• Me-first — 2007-08-22
• Having I-strain? — 2007-01-04
• Like a 44-Across — 2000-10-18
• Having an "I" problem? — 2000-07-05
• Dog-in-the-manger — 1999-01-02