Sam M's "Hair" looks back at a relationship through one small argument that grew into something much bigger. The speaker gave in and got their hair cut, but the real trouble came afterward: they "messed up," said hurtful things, and lost the other person's trust. The short lines, with words like "Big time" and "A lot" sitting alone, make the fighting feel blunt and heavy.
The feeling at the center is mixed. The speaker admits they don't know whether to be "grateful / Or sad," because the conflict seems to bring something good each time. That idea leads to a softer turn, where the speaker sees the other person's "sweet side" again and feels themselves falling in love once more. They even hope the feeling is now shared.
The mood moves from tense and regretful to tender and hopeful. The last line, "It started with hair," adds a note of wonder, and maybe a little humor, at how trivial the beginning was.