The classic example is
Colleague: "Hi".
One hour passes
You: "Hey - what's up, can I help you with something?"
10 minutes pass
Colleague: "Yeah I was wondering if I could ask you about Foo"
One hour passes
You: "Sure, what do you need to know?"
Next day
Colleague: "I'm trying to export but it's not working."
One hour passes
You: "Okay... Is it giving you any error messages? Please give me as much info as you can in one go!"
etc...