Among Catholics, disbelief in hell is heresy. That is a problem today, when the swing of the cultural pendulum has made easy universalism more common than the old rigoristic exclusivism. More common, however, is treating the possibility of hell as unimportant. That is the result of faulty understanding, which often arises from faulty emphases in teaching. As a corrective, I also recommend Cardinal Dulles' "The Population of Hell." (That essay used to be easy to access at the First Things website. But they're revamping as I write; and as we all know, progress entails deterioration.)
Many spiritually immature and/or theologically ill-formed people assumed, and still assume, that hell is a fiery place one gets sent to by God for being bad. Those who believe there really is such a hell accordingly believe in a vengeful God. Others, disbelieving such things, believe there is no hell at all. Both groups are wrong; as a result, many from each lose their faith. Fortunately for the former, they recognize the problem with that more often than the latter.
The fire of hell is best conceived as the suffering of those who, by dint of grace sufficient for the salvation of all, have been given eternal life willy-nilly, but on terms they reject. Hell is what one gets when, starting even in this life, one prefers suffering to accepting life on God's terms as revealed in Jesus Christ. That, and only that, is the attitude of the confirmed reprobate. Such people condemn themselves; for them, the love of God is torture because they cannot reciprocate it, and the pain of loss in the hereafter is the resulting impossibility of union with God.
The words of Jesus make unmistakeably clear that becoming such a person is a real possibility one must work to minimize. (I've never understood people who think Jesus preached a nice religion and St. Paul a nasty one. The former talks about hell much more than the latter.) My own spiritual journey verifies the Lord's message. Sometimes I rage at God for being at least complicit in life as it is for me, and for so many others who have it worse than I. Such resentment should of course lessen over time with faithfulness, objectivity, prayer, and all the usual spiritual tools. But unless one is already a saint, fear of hell is often useful and sometimes necessary for the purpose.
For that reason, I have little use for priests who never mention even the possibility of damnation. They're mostly the same ones who see nothing wrong with cafeteria Catholicism, so long as their flock picks the same items they do from the cafeteria. As a result, I can't even eat in cafeterias anymore. That's at least a step away from hell.