The cognitive science literature consistently points at individual and group differences in spatial abilities (e.g., Hegarty, Montello, Richardson, Ishikawa, & Lovelace, 2006). This means a complex graphic may not be equally complex for everyone (or a simple graphic may not be equally simple for everyone). When personalization is not possible (which often it is not), it is possibly best to adjust the design for people with lower spatial abilities – or, as some will say in user interface (UX) design community, design as if “the user is drunk” (http://theuserisdrunk.com/). While designs that are optimized for a low-spatial population may be frustrating for the high-spatial viewers at times, or it may even slow them down a little, it should not necessarily harm communication in the long-run. It is, though, important to remember that spatial abilities can be trained, and may also involuntarily change by age. This is also true for visual abilities, e.g., approximately 8% of the male population has color deficiencies (Chan, Goh, & Tan, 2014) , and as we age, we lose some of our color receptors (Roy, Podgor, Collier, & Gunkel, 1991), and reportedly, up to 20% of the population has some difficulty in seeing stereo (Ware, 2004). If you exclusively target a particular age group (children vs. adults, professionals vs. senior citizens), or otherwise are able to assess the spatial abilities of the potential viewers, personalizing the visual for them is, of course, the most recommendable course of action.  While opportunities for true “personalization” are rare, thinking deeply about audience in creating (and/or customizing) a visualization is always possible, and desirable.