What is the term for having a friendly, pleasant attitude?

The term that best describes having a friendly, pleasant attitude is "friendly." This word directly conveys warmth, approachability, and a positive attitude towards others, encapsulating the essence of being amicable and congenial.

While "affable," "agreeable," and "companionable" also suggest positive interactions or relationships, they may not fully carry the same broad and universally understood connotation of friendliness as "friendly" does. For example, "affable" suggests someone who is easy to talk to but might not capture the full depth of warmth implied by "friendly." "Agreeable" denotes a willingness to agree or a pleasant disposition, but it may lack the personal warmth associated with being friendly. "Companionable" emphasizes companionship and pleasantness in a social context but does not necessarily imply an overall friendly demeanor.

In summary, "friendly" is the most comprehensive and straightforward term for having a friendly, pleasant attitude, making it the best choice in this context.