Terrible example I've just made up:
Jimmy lined up his feet on the free-throw line and crouched low for a moment, catching his breath. The tricky swoop-basket he'd invented and practiced a thousand times at home alone would win this game... IF he managed to make it in front of an audience. He stood, lifted his arms, and threw with all his might, then watched as the orange ball arced toward the basket.If you're anything like me, by now you are tearing your hair out going OMG WTF DID HE MAKE THE BASKET????? WHY IS THE BALL TAKING SO LONG??!
Everyone always called him a shrimp, but Jimmy was determined to show them all he was the toughest little shrimp around. He could trash-talk better than any kid at his school. His step-dad always said, "what Jimmy lacks in height, he makes up for in mouth!" and that was pretty much the truth. But he had been working on this basket for days and days, even forgoing his favorite pepperoni-and-pineapple pizza at lunch because he heard somewhere that hunger gives athletes an edge.
His stomach rumbled. Man, maybe skipping the pizza was a mistake. If this was an 'edge' he'd rather not have it.
HEY SHRIMP, Kevin yelled from the sidelines. NICE SHORTS! Jimmy looked down at his shorts in dismay. Aw man, the juice he spilled before the game looks like a pee-stain. Ugh. Can't he go one day without dropping something on himself? He looked back at Kevin. "NICE FACE, DILLWEED!" he shouted.
Please don't do this to your reader. If you start a short action - by which I mean a literal physical movement or act - follow through. Throwing a ball, skipping a rock, taking a bite, sneezing, giving a hug... let the character do these things THEN move on, don't interrupt him or her right in the middle of it to talk about five other things.
Now, if the character is making dinner, that is a big act comprised of many small actions. So it is fine if the character has thoughts or conversations or reminisces about things or whatever while dinner-making is going on. But if you start an action like "Sarah began salting the roast" and then go off for five paragraphs about something else and then come back and the Sarah is STILL SALTING... I'm going to be worried about her blood pressure, at least. Or assume she is just a terrible, terrible cook. If that's what you're going for, then by all means carry on. Otherwise, let her finish salting quickly THEN go off on a tangent.
"Sarah salted the roast, then lifted the heavy steel pan into the wall-mounted oven with a grunt. 'Nothing like a home cooked meal', she muttered to herself. Then she thought about the arsenic she'd added to the cornbread, and laughed out loud."