Recently I sent a mail wishing a friend well. I ended it with the following sentence.
Please take care, and call me if you need anything.
The comma was included because the two were separate thoughts with the latter as an add-on to the former. Consider it without the comma.
Please take care and call me if you need anything.
While grammatically correct, it sounds like a to-do list--please do the following things: (1) Take care, (2) Call me if you need anything.
Would you agree? I see this cropping up in a lot of writing here and there.
I phoned my wife, and slept for 2 hours
seems to be a description of the list of things I did this afternoon, while
I phoned my wife and slept for 2 hours
sounds like I'm reporting a very boring conversation.