I asked a colleague to give me a short tour of their lab to see how they have established it. Later, I followed up saying I was still interested in visiting their lab. They told me that they would reach out with a date later after their major deadline. It's been a while since that deadline passed and I have not been invited until now. My colleague gave a similar tour to another person after the above-mentioned deadline passed yet I was not invited. So, I assume my colleague was not interested in giving me the tour. I thought it was okay--even though I felt bad--since it's up to them to decide whom to invite or not invite.
Later, the same colleague asked me for a favor to do a task that was up to them to complete. The task requires a qualified person who is good enough to make intellectual judgments. So they may be asking me to do the task because 1) I am one of the qualified persons and 2) it may not necessarily be a good use of their time or fun to do the task.
Officially, neither I nor my colleague have obligations/incentives to work together with or fulfill requests from each other. I am in a transitional job in my current position. The only incentive for me to accept their request is to maintain a good working relationship if I accept a long-term position in my current office--an option I consider a possibility for now.
Personally, I don't want to refuse their request because I like helping people. Helping them with the requested task may not be necessarily a good use of my time and beneficial for me. But I don't mind fulfilling someone's request if they ask and I can help. But, I am also not happy that they silently refused my request earlier and now asking for a favor which is also not a good use of my time either.
I don't want to say "You rejected my request earlier and now you are requesting a favor which is not a good use of my time either" directly or indirectly. But I want to make them realize that mutual respect is important in a collegial relationship. How should I do that?
Note: this happened in academia. So, I posted here.
Update: I asked in workplace and interpersonal skills. But was not well received in both platforms. People in both platforms suggested this post does not belong there.