Seforim Hakdoshim repeatedly refer to machlokes as a fire and continuously exhort us to guard ourselves from this deadly fire. The של״ה הקדוש (שער האותיות ב יד) says that the issur of machlokes is in regard to even a משהו, a minuscule amount. Many issurim are not relevant when there is only a drop, however the של״ה expresses that even a tiny dispute must be avoided. Just like a tiny spark can cause a huge conflagration and even a tiny fire can destroy wantonly, causing irreparable damage, even a small dispute can have everlasting repercussions.
Chazal (סנהדרין דף ז.) compare strife to a river that overflows her banks. If one notices the imminent surge before the river has actually started overflowing, a strong barrier can be erected in order to prevent the impending flood. If, however, it is not erected in time, the raging waters can no longer be contained, and the fields cannot be salvaged. The Gemara quotes a possuk in משלי (יז יד) פוטר מים ראשית מדון, if you deal with the first drop of water, a gigantic flood can be avoided. So too, dealing with strife right away can avoid a large-scale machlokes. By ignoring it, however, the raging machloke can not be contained or salvaged.