While I admit to have used this word in the past week I highly recommend trying to use it sparingly, as opposed to your default method of agreeing to something, and also be deliberate with it.
Agreeing to something with the word “sure” it telling the person, identifying the situation and/or admitting to yourself that – you’d rather be doing something else – you’ll do it begrudgingly – you aren’t really on board with this as a proper use to of your time….(the same thing).
The word “sure” is at very high risk of being seen as passive aggressive. Does the use of this word motivate your team? Does it create an air of “meh” among the family/team/company? Does it tell your manager you are not fully in?
What are you saying top yourself if “sure” is all you can come up with. We all do shit we aren’t stoked on or “have to do” as a means to an end. We all have to take out the trash.
Check out Derek Sivers’ philosophy of “Hell Yeah or No”. This is the antithesis of “sure”.
Finally, there is a time to use “sure” but it should followed by a push for changing the micro or macro whatever circumstance (often your attitude) that led to using “sure” instead of “yes” or better, “HELL YEAH”.