Use this phrase to explain what you're doing, and make it sound like a sudden decision rather than something which was planned out in advance.
I just thought I'd call and see if you wanted to have lunch some time this week.
You could also say it this way:
I wanted to call and ask if you wanted to have lunch some time this week.
But "I wanted to ___" doesn't tell how long you wanted to do something. It could mean any of these:
- You've wanted to do it for a long time.
- You just decided that you want to do it.
- You wanted to do it in the past, but now you don't.
"I just thought I'd ___" expresses the idea of deciding quickly and without thinking too carefully about something. Here are some other examples:
No, there's no special occasion; I just thought I'd clean up a little bit.
Hey. Are you OK? I just thought I'd see if you needed any help.