Accountants have so many projects. So many tasks, and so many DEADLINES! Sometimes we deliver when we say we will. Sometimes we don't, and some people are a lot better at this than others. The ability to execute and be dependable in your execution affects everyone because accounting is a team sport.
One thing I'd really like to see more of .... A leader acknowledging a simple occurrence. Somebody on their team said they would do something by a certain time -- and they did it!
The acknowledgement does not have to be grand.
When is the last time someone delivered when they said they would and you simply .... reminded them?
"Hey - You told me you would get that report done by Friday and you did. Thanks I appreciate your on time delivery."
And keep doing this. Don't stop. Reinforce the positive behavior. Remind the other person that they simply did what they said they would do. Watch what happens.