You're reading a German news article and you hit the word "Gift." You know this word. It means gift, a present, something nice. Except in German it means poison, and the sentence you just read confidently backwards was actually a warning label or a news item about a toxin, not a birthday. This is the specific danger of a false friend: unlike an unfamiliar word, which stops you and makes you look something up, a false friend feels familiar. It doesn't slow you down. It just quietly hands you the wrong meaning and lets you keep reading, sometimes for several sentences, before something stops making sense.
German and English share a huge amount of vocabulary, close enough in spelling and sound that your brain pattern-matches to the English meaning by reflex. Most of the time that reflex is right. A handful of words is where it fails, and those words show up in real writing often enough to matter.
The false friends that actually cause misreadings
Gift means poison, not a present. A gift in the English sense is ein Geschenk.
Bekommen means to get or receive, not to become. "Ich bekomme ein Buch" means "I'm getting a book," not "I'm becoming a book." To become something is werden.
Also means "so" or "therefore," used to start a sentence the way an English speaker might say "well then." It does not mean "also" in the sense of "in addition." That's auch.
Rat means advice, not the rodent. "Ich brauche deinen Rat" is "I need your advice." The animal is eine Ratte.
Chef means boss or manager, in any workplace, not specifically someone who cooks. A cook is ein Koch.
Handy means cell phone. It's a noun, and it's the normal everyday German word for the device in your pocket, not an adjective describing something useful.
Mist doesn't mean fog or haze, it means manure, and by extension it's a mild swear word roughly like "crap." Fog is der Nebel.
Bald means soon, not hairless. "Ich komme bald" means "I'm coming soon."
Fast means almost, not quick. "Ich bin fast fertig" is "I'm almost done," not "I'm quickly done." Quick is schnell.
Sensibel means sensitive (as in easily affected, emotionally or physically), not sensible in the English sense of reasonable or practical. Sensible in that sense is vernünftig.
Aktuell means current or up to date, not actual. "Das aktuelle Problem" is "the current problem." Actual, as in "real" versus "hypothetical," is tatsächlich.
Why these specific words, and not others, cause the problem
Most German-English false friends trace back to the same source: two languages that share a huge amount of vocabulary through a common Germanic root or through parallel borrowing from Latin and French, where the meaning drifted apart over centuries in one language but not the other. Bekommen and "become" share an old Germanic root meaning roughly "to come by" or "to arrive at," and German kept a meaning closer to "to arrive at (something you receive)" while English narrowed to "to arrive at (a new state)." Gift and English "gift" both trace to the same Germanic root for "something given," and the German meaning narrowed toward a specific, unpleasant kind of giving, poison as something administered, while English kept the neutral, positive sense.
Knowing the etymology doesn't prevent the mistake in the moment, but it does explain why these particular words, out of thousands of shared-looking words, are the ones that misfire. The safe cognates (Familie, Musik, Universität) share meaning and history cleanly. The false friends are the ones where that history took a turn.
Catching yourself mid-sentence
The reliable signal isn't the word itself, it's the sentence not quite making sense once you plug in the assumed English meaning. If a German sentence about a chemical spill mentions "Gift" and your instinct reads it as "gift," the sentence stops being coherent, a chemical spill doesn't involve presents. That moment of the sentence not quite landing is worth trusting rather than pushing past. A short mental list of the words above, reviewed occasionally rather than memorized once and forgotten, is enough to start catching most of them on sight within real reading, rather than needing to consciously check every familiar-looking word as you go.
This is a narrower, more targeted problem than German's better-known reading obstacles, the verb-final clauses and separable prefixes that stall app-trained readers once they move to real text. Both are worth knowing before you hit them in a real article rather than after.