Look what was in my e-mail bag!

Subject line: do the world a favor

please...no more comics, their terrible. You've wasted too much time!

The amount of time that I have simply wasted is my biggest regret but I cannot undo the past. No Ctrl-Z in real life.

English is a difficult language and I applaud you for getting it almost right. Homonyms are tough. The word you are looking for is they're, a contraction of they are.

Thank you for taking a moment of your time to compose and send your electronic missive.

Do something good for humanity - sterilization.