* His ambition. Caesar was a very ambitious man, and he often put his own personal goals ahead of the interests of the Roman Republic. For example, he led a military campaign against the Gauls in 58 BC, even though the Roman Senate had not approved the campaign. Caesar's victory in Gaul made him very popular with the Roman people, but it also made him a powerful enemy of the Senate.
* His authoritarianism. Caesar was also a very authoritarian leader. He did not consult with the Senate or the Roman people on important decisions, and he often bypassed traditional Roman political procedures. This made him even more unpopular with the Senate, which saw him as a threat to their power.
* His wealth. Caesar was also very wealthy, and he used his wealth to buy political support and to build up a loyal following. This made him even more unpopular with the Roman people, who saw him as a corrupt and self-serving politician.
* His sexual escapades. Caesar was also known for his sexual escapades, and he was rumored to have had affairs with other men as well as women. This made him even more unpopular with the Roman people, who were very conservative in their sexual views.
In conclusion, there were a number of reasons why Julius Caesar was unpopular with some Romans. His ambition, authoritarianism, wealth, and sexual escapades all contributed to his unpopularity.