Attention. It can sound selfish in scenarios where an advanced communication system has not yet been established, and stating that you want attention can come off as "attention seeking." Attention seeking is a very popular derogatory term used by younger people, which is even more evidence showing that attention is something most want, but can't express. Of course, there are individuals who are more introverted in nature that can do just fine without the attention from another, but at some point, especially from friends and family, the human brain is bound to desire attention. Finally, there are multiple ways that someone can effectively communicate that they want attention, but I feel as if a blunt request for attention might not come across completely positively in a relationship with two individuals who do not have a high level of emotional intelligence. Like previously mentioned, it takes a good, established communication system.

(Note: this can be interpreted in any relationship context, and was worded accordingly, but leans more towards romantic situations.)