I guess for me it would be heights. The other day I had to get the ladder and climb up to the top of it to get Cinnamon down from a plant shelf in the kitchen. Ok, so the ladder was around 8 feet or so, but high enough for me. And, I wouldn't say I am claustrophobic, but I really don't like to be in small, enlcosed spaces or having people (except for my husband) stand close to me.