Is It Wrong to Be Stringent?
Understanding when religious stringencies are appropriate: should everyone adopt extra strictness or is it only for the spiritually elevated?

Is everyone permitted to take on personal religious stringencies as they wish?
Regarding waiting between eating meat and dairy, the Talmud relates (translated from Aramaic): Mar Ukva said (Mar Ukva was a sage of the Talmud), regarding waiting between eating meat and dairy, I am considered "vinegar, the son of wine" (an expression for a son who doesn't reach his father's level). For my father, if he ate meat now, he wouldn't eat cheese until twenty-four hours had passed, while I don't eat meat and then cheese in the same meal, but I do eat cheese in the next meal (meaning after six hours). The commentators questioned why Mar Ukva, who was pious and holy, called himself "vinegar, the son of wine" over such a minor matter – couldn't he have also been stringent and waited twenty-four hours before eating dairy?
The Chida in his book Arvei Nachal wrote that Mar Ukva's decision not to be as stringent as his father was based on the principle stated in Tractate Berachot (16b): "Not everyone who wishes to take on a reputation should take it," referring to those who mechanically imitate what they see their teachers doing, despite being far from their spiritual level.
However, if someone experiences a stumbling block, they may adopt whatever stringencies they need to protect themselves. This is illustrated in the responsa of Maharam of Rothenburg, who used to mock people who were stringent about not eating meat after cheese (which isn't strictly required by law – only after eating meat must one wait six hours before eating dairy, but after eating cheese there's no strict obligation to wait, and cleaning one's mouth and hands is sufficient). In fact, he thought their custom went against Torah principles since there was no basis for such stringency in the Talmud. But once, Maharam of Rothenburg found cheese between his teeth after a meal, and he decreed upon himself to be stringent about meat after cheese just as with cheese after meat.
In the Rema's responsa, he wrote to a scholar who wanted to be stringent in a matter that was entirely permissible according to the strict law, saying he wasn't permitted to be stringent because "isn't what the Torah has forbidden enough for you, that you forbid other things to yourself?" Nevertheless, many authorities hold that a person may be stringent in matters they feel concerned about, whether due to doubt or to protect themselves from stumbling.
More than ten years ago, Rabbi Ovadia Yosef told the scholars at the Yechaveh Da'at study hall in Jerusalem that it's appropriate for a Torah scholar to add personal stringencies as much as possible, taking into account the opinions of various authorities, even though the law has been decided leniently against their views.
It's understood that these matters require great wisdom, especially in our time when some err by taking on excessive stringencies that cause more harm than good. On the other hand, one should always strive to rise higher, continually adding to one's observance of commandments and service of Hashem.
Rulings of Rabbi Ovadia Yosef courtesy of "Daily Halacha" website