Atajos means “shortcuts,” or quicker routes to reach a destination. In the song, “has sido más de atajos que subir escaleras” uses it metaphorically to suggest that she prefers easier, less direct paths in life rather than working her way upward step by step, making it a vivid and memorable expression.
Envido6 takes us back to a Spanish secondary school in 2007, where he was the odd new kid and she was "la reina del baile" [the queen of the dance]. He learned her name on day one, she spent breaks smoking in the toilets, and he admits he failed French "porque me sentaba a tu lado" [because I sat next to you]. That detail is so specific and so silly that you believe every word. Instituto is Spanish secondary school, and los patios are the breaks spent out in the playground.
The title is Disney's Lady and the Tramp, which is called La dama y el vagabundo in Spain: "tú eres una dama, y yo, un vagabundo, aunque ladre" [you are a lady, and I am a tramp, even if I bark]. He's the scruffy dog, and the barking joke is great. Then he swaps films: "tú eres Bella y yo soy Bestia" [you're Beauty and I'm the Beast]. Three years on, the boys born in '94 are still betting on her coming back, and "Se paga quince a uno" [it pays fifteen to one] is bookmaker talk for long odds. The best line might be "la suerte es solo un punto de vista" [luck is only a point of view], straight after a joke about the cats who spent one of their lives on her. The song ends on a messy spoken bit: someone calls out to their dad and insists they haven't finished yet.