They have different hobbies and thus lack common topics.
Examples (Wiktionary)
Mandarin
缺乏
缺乏
quē fá
to lack; to be short of
Mandarin
缺乏常识
缺乏常識
quē fá cháng shí
to lack common sense
Mandarin
庸俗的事务主义家不是这样，他们尊重经验而看轻理论，因而不能通观客观过程的全体，缺乏明确的方针，没有远大的前途，沾沾自喜于一得之功和一孔之见。
庸俗的事務主義家不是這樣，他們尊重經驗而看輕理論，因而不能通觀客觀過程的全體，缺乏明確的方針，沒有遠大的前途，沾沾自喜於一得之功和一孔之見。
yōng sú de shì wù zhǔ yì jiā bù shì zhè yàng ， tā men zūn zhòng jīng yàn ér kàn qīng lǐ lùn ， yī né r5 bù néng tōng guān kè guān guò chéng de quán tǐ ， quē fá míng què de fāng zhēn ， méi yǒu yuǎn dà de qián tú ， zhān zhān zì xǐ yú yī dé zhī gōng hé yī kǒng zhī jiàn ．
As against this, vulgar “practical people” respect experience but despise theory, and therefore cannot have a comprehensive view of an entire objective process, lack clear direction and long-range perspective, and are complacent over occasional successes and glimpses of the truth.
Mandarin
缺乏深度
缺乏深度
quē fá shēn dù
to lack depth
Mandarin
他们的长处，正如斯大林说过的，是对于新鲜事物有锐敏的感觉，因而有高度的热情和积极性，而在这一点上，有些老干部则正是缺乏的。
他們的長處，正如斯大林説過的，是對於新鮮事物有鋭敏的感覺，因而有高度的熱情和積極性，而在這一點上，有些老幹部則正是缺乏的。
tā men de cháng chù ， zhèng rú sī dà lín shuō guò de ， shì duì yú xīn xiān shì wù yǒu ruì mǐn de gǎn jué ， yī né r5 yǒu gāo dù de rè qíng hé jī jí xìng ， ér zài zhè yī diǎn shàng ， yǒu xiē lǎo gàn bù zé zhèng shì quē fá de ．
The strong point of the new cadres, as Stalin has said, is that they are acutely sensitive to what is new and are therefore enthusiastic and active to a high degree—the very qualities which some of the old cadres lack.