It cuts two ways ...
If you are rude or aggressive towards any Customs / Border Force when they ask you questions, or you are defensive about those questions then they are likely to throw the book at you. And rightly so.
By equal measure, if they give you 'a second chance' e.g. "please go and dispose of that fruit of yours on those picnic benches over there" then smile and say "thank you". Whether you eat all that fruit is up to you.
On the other hand, if they are just being a$$holes for the sake of it then there are things you can do .. like someone I knew who got pulled for accidentally having a very few ml too much perfume / after shave on him. And they really went to town on him ..
So he held up the offending item and asked if that was the problem .. "Yes, now pay up" was the uncompromising reply. Oops, he then 'accidentally'
dropped it. It did apparantly make customs smell much nicer for a while.