'anger' is actually an illusion: it doesn't exist. There doesnt seem to be any noncircular definition/ description of it either. So just be glad someone is nice & interested to share their time with you. An empirical example too: Knew a very learned busy kind person who came to an appreciated understanding with their folks that talks re 'important things' would only occur if genuinely very pressing, and then hopefully of under 2to3 minutes duration. That all communications would hopefully be about the weather, birds, shika, squirrels,  lunch, what might be for dinner, songs, water, tree growth, scenic vistas, walking around, etc. That was much more important to them, inane chatter. Priceless. No hustlebustle. Seems like wise decision.

And because of time constraints, maybe simply reduce duration of calls by a few percent. Laugh and share joy & tell them you have to go for then, and thank them for talking with you. Isnt a biggee: straightforward and honest & ok! 

Whether what they talk about seems important, apparently its important to them, so: ok! Or adjust the subjects a bit. Discuss the weather and nutrition or something, something upbeat & optimistic. Very good. Uplifting maybe. Have some nice tea while on the phone(just notspilling it into the phone etc)

And if irritation, simply discontinue it. Irritation probably wouldnt adjust anything in a useful direction anyway. And the situation doesnt really sound bratty, & if it really seems like it is, then simply discontinue brattiness. Good. And much less tedious than fretting over it. Much easier too. and sort of like being honest, theres less to keep track of. 

And every time is new, every moment can be appreciated. Invest in good happy kindly things rather than self indulgent tedious things, such as that discarded illusion commented on at the outset! 

And always try do the best one can: cant do any better than that!