An opponent being able to remove one of your lands with small creature removal or any ping effect or -1/-1 counter is scary. It sees play (I think) in Legacy a

An opponent being able to remove one of your lands with small creature removal or any ping effect or -1/-1 counter is scary. It sees play (I think) in Legacy and Commander where there are a bunch of specific powerful ways to abuse it (e.g., combo off early with Arbor + Gaea's Cradle to generate a bunch of mana), but you're not going to pull that off often in cube, so it would mostly be a basic forest that your opponent can easily remove.