1) The Bahá'í Faith exists solely to perpetuate itself, 99% of its focus and activities are toward this one goal, growth in membership. Throughout their history they have been preparing their members for the "entry by troops" of new converts, which has yet to materialize. They do a minimal amount of humanitarian or charity work.
2) Bahá'ís use terminology in ways that was not intended. Bahá'ís don't have censorship, they have "review." They don't proselytize, they "teach." They don't have missionaries, they have "pioneers." They don't have prophets, they are called "manifestations." And so forth.
3) Bahá'ís have a "lo is us" sense of historical persecution. If you look at their history, though, most would call it just fruits. During the founding of the religion, the forebear Babi sect led a violent revolution in Iran, and some of their members later attempted to assassinate the Shah. Their leadership were exiled to the Ottoman Empire where schismatic violence within the group later led to house arrest. Of course, this is all billed as being persecuted.
4) Bahá'ís lament how others view them in a conspiratorial light, when in fact, again, this is based on historical reality. In Iran the Babis had the protection of the Russian ambassador (Russia being an imperial power that had seized wide swaths of territory from Iran and at one point the Russian ambassador had to approve Iranian cabinet ministers). In the Ottoman Empire, Bahá'ís conspired with the Young Turks, who deposed Sultan Abdul Hamid II in a coup. Later, they would assist the British, and their leader 'Abdu'l-Bahá earned knighthood, being designated KBE. With their headquarters in Haifa, Bahá'ís have cooperated with the state of Israel, to the extent that some of the Bahá'í World Center buildings are built on land expropriated from absentee Palestinian land owners.
5) Bahá'ís inflate their membership numbers. Comparing census data of various nations to self-reported data confirms this. The outside data Bahá'ís often cite, like from the Association of Religion Data Archives, only uses self-reported data, creating a circle.
6) Bahá'ís initially hide from members some of the more unsavory realities of their religion. Men and women are equal, but women are barred from serving in the highest organ of the religion, the Universal House of Justice. The hierarchy is billed as being democratic, but only in the sense of council democracy as it still exists in Cuba where individuals elect local committees, who then elect national committees, who then elect the Universal House of Justice. There is a parallel appointed hierarchy. With no politicking or partisanship allowed, elected members in the higher ranks serve for life until they die or retire, and are subsequently replaced by nomenklatura.
7) Bahá'ís hide from members some of the more unsavory realities of their history. After Bahá'u'lláh their leader was 'Abdu'l-Bahá and then Shoghi Effendi. By the time Shoghi Effendi died, all the living descendants of Bahá'u'lláh had been excommunicated from the religion for various offenses, including "marrying a low born Christian girl." Shoghi Effendi was also designated the "Guardian," by 'Abdu'l-Bahá. The Guardian was supposed to designate subsequent Guardians, but did not do so, although the entire Bahá'í administrative structure depended on it.
8) Ignoring failed prophecies, like `Abdu'l-Bahá declaring the peace of the world to come by the year 2000. Those of us around in the 1980's and 1990's remember the crescendo, and the anticlimactic ignoring of reality and denial of the build up.
9) Bahá'ís claim earlier religions are valid, but in reality they only do this in an Islamic sense (i.e., the earlier revelation was perverted over time). For example, they deny the parts of Bible written by Paul. Or when Muhammad says he is the last prophet, Bahá'ís say that was true only for the Adamic Cycle, but now we are in the Bahá'í Cycle.
I could go on,