There are are beaches and beaches. Nice firm yellow sand that's good for digging and sandcastles, shallow slope and tame waves, and sandbars so you get little pools as the tide goes out - perfect. Sunny but not too hot, no wind, ice cream van and toilets and you have a great day. I just love it when the kids get into a big group to dig moats and channels to the water as the tide comes in, and the adults get sucked in too.
Strong waves, anxiety-inducing rocks that kids are desperate to climb on, horrible dogs, crappy sand, rotting dead seagulls, no facilities, nasty sand fleas hopping everywhere, windy so sand constantly in your face and picnic - yuk.
First find the right beach, then improve things by taking a mini tent to shelter/change/chuck stuff in, a really nice picnic complete with properly iced cool bag, wine, hat and shades, wipes, kitchen roll and suncream, and plenty of towels or those towelling beach cover-up things for when kids get cold in the water.
You have to give up on the idea of getting a break before you go (unless you have other adults to do the supervising).