A man has told a court in Belfast that a bakery's refusal to make a cake with a slogan in support of gay marriage made him "feel like a lesser person".
Ashers Baking Company faces a discrimination case, brought with the support of the Equality Commission.
Gareth Lee said he was treated with courtesy when he placed the order, but the bakery later said it could not fulfil it as it was a Christian firm.
He said the woman who telephoned him about this was apologetic.
However, he said he felt he was not worthy of service because he was gay.
Mr Lee said: "I expressed disbelief. I couldn't believe it was happening. This is Northern Ireland. This shouldn't happen."
He told a barrister for the firm he later realised he had been dealing with the firm's owner, Karen McArthur.
Mr Lee told the County Court in Belfast: "I wasn't asking anyone to support my views on anything.
"It was just an everyday transaction."
Mr Lee wanted the cake to include a slogan that said "support gay marriage" along with a picture of Bert and Ernie from Sesame Street, and the logo of the Queerspace organisation.
Earlier on Thursday, the court was told by Mr Lee's barrister that the company had broken the law by turning down his order.
He said Mr Lee was a regular customer who had ordered the cake after seeing an advertising leaflet in the shop for its custom-made baking service.
The leaflet made no reference to any restrictions on the type of cakes available, he said.
'David and Goliath'
The barrister said it later emerged it was one of the controlling directors who had taken the order but had not advised Mr Lee that there was a problem.
He said while some had portrayed Ashers as 'David' to the Equality Commission's 'Goliath', it was a firm with more than 60 staff that supplies convenience stores and delivers cakes in the UK and Republic of Ireland.
"This is a case about a single man who had a contract for a cake which was accepted by a substantial, international million pound business of many employees," he said.
"You might say that Mr Lee is the David and Ashers the Goliath."
He said Ashers was a large business which "cannot be allowed to break a contract with a single individual over small sums of money" in a way that breached the law.
"If that is allowed and one takes into account the relevant size of the different organisations and persons in this litigation, the rule of law is worth nothing," the barrister said.
Speaking outside court in Belfast on Thursday morning ahead of the civil case, the bakery's general manager said he wished it had not resulted in a court case.
Daniel McArthur said the company's problem "was with the message not the customer" and that it went against their "sincerely held beliefs".
The case continues.