In his own words
Sonnet 30
When to the sessions of sweet silent thoughtI summon up remembrance of things past,I sigh the lack of many a thing I sought,And with old woes new wail my dear time’s waste:Then can I drown an eye, unused to flow,For precious friends hid in death’s dateless night,And weep afresh love’s long since cancell’d woe,And moan the expense of many a vanish’d sight:Then can I grieve at grievances foregone,And heavily from woe to woe tell o’erThe sad account of fore-bemoaned moan,Which I new pay as if not paid before. But if the while I think on thee, dear friend, All losses are restor’d and sorrows end.
Grief kept like an account book: old losses summoned to court and paid again in full. Thinking of one friend closes every account. Where 29 turns on joy, this one turns on restoration.