If the UK goes "full retard" with a Hard Brexit to WTO terms it will impact our economy by 7%, so we should make it very clear to the UK that if they are stupid enough to expect us to roll over for them we'll use our veto the first chance we get to cause maximum damage.
The only deal we would even consider vetoing is a Brexit deal which included an agreed hard border. We would never agree to that. But neither will the EU, so we won't have to deploy our veto to avoid it; no such deal will ever be put to us. Plus, the UK government is also committed to avoiding a hard border; they have said this consistently. So saying that we would veto a deal that provided for a hard border is not offensive, threatening or bullying to the UK; all we are saying is that we would veto a deal which the UK itself does not want.
It might be offensive to ultra-Brexiters, who actively want a no-deal Brexit and a hard border and believe that the UK government should be targetting it. But they are a small minority and, despite their Mussolini-like delusions, do not embody or represent the United Kingdom. If they take offence at our defence of our own interests, well, I can live with that. But I will deride anyone who says that, by offending them, we are "bullying the United Kingdom".