Taking advantage of the Telegram from the summer of 2017, I was generally pleased with its convenience, although there were scattered moments. But everything has changed since the very moment when I recently decided to start my telegram channel, and this will be my confession about painful things.
At once I want to note that for me the standard of convenience is the messages of VKontakte and Instagram. It is worth emphasizing that in the latter there is a very poor functional, but such a service is not necessary anymore. So let's get started.
Picture and text
It would seem that it may be easier than such a simple bundle as a picture + text to it. But anyway, a text description can be attached to a picture only if it is single in your message and the text is placed under the picture, like this:

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You probably won’t believe me, but I only learned about the possibility of making a description for a picture after 3 months of using a telegram. It happened by chance when my girlfriend sent me a photo accompanied by text. In my opinion, the way of specifying the description of the picture in the telegram is not very obvious.
If we load together 2 or more pictures (good, in one of the latest updates it became possible), then we can write a description under one of them, and leave the rest empty. This will be taken as a description of the post and the text will be made under the image. But as soon as we make a description for two pictures, how this is already perceived by the description of the picture, which has a damn bad effect on the generation and design of content for channel owners. Agree to clap on each picture and read its description, which is limited to two hundred characters, is not very convenient. The Telegraph comes to the rescue here, but you still have to click on it. And then back to the tape.
The text located under the image also seems to me not a very good choice. I understand the semantic approach of the picture-its description, but after all we are all used to seeing the text and already below it the accompanying picture. This is normal, since the image, in most cases, only hints at the subject of the story, and the text is the key element of the post.
How can I fix this? It would be very nice in the future to get the opportunity to do the description just for the post as a whole, and not just for its individual elements. Such a simple but very useful function could simplify the life of all Telegram users and make interaction with it a little (much!) More convenient and more pleasant.
Favorite Posts
Yes, this is what we lacked in messengers! And I do not understand why this possibility was not immediately realized in Telegram and its predecessors. Convenient, useful, practical, especially now that when sending a message, the “favorites” is always attached to the top of all chats, but something is still wrong.
Instead of 3 actions: tap to a message - send - tap to the “favorites” block can be made 2, and much simpler.
To do this, simply in the pop-up menu when you click on the message, you must add the button "To Favorites." Bingo. Thus, the message we need can be saved to us in two quick tapas. Mastkhev as for me, Pasha, take a note!
Username
We have two names of some kind. A little confused.

What distinguishes the name of the user name? And if I change the username, the name above will change? And if I am a user and want to change the name in the upper column, whose name will I change? And if I change, then I am a user? Okay, enough. In order to avoid such confusion, you only need to change the name of the “username” line to, say, “your nickname”, “public link to your account” or “ID”, I don’t know what the essence of this is better to convey.
Self-destruct account and autoload media
Any operations that occur without the knowledge of the user - a bad tone in the UX. Item about self-destruction account buried far in the settings and the default is set for 6 months. If you do this, then at least inform the user about it when registering or first meeting with the application.

Similarly with media. By default, any materials, be it a picture, video or document (full list in the screenshot) are saved to your device. Your memory is slowly filling up, and you don’t even understand why this is happening. In addition to all, all this data is cached so that, for example, a picture saved by telegram is not displayed in my gallery, and the music is in the player. I understand that this was done with the goal of quickly uploading information directly to Telegram itself, but I would prefer a thin initial setting of my account than when everything was already decided for me.

Bots
Yes, most of the interactions of an ordinary user with them sometimes cause a wild pain of the fifth point. Bots are multifunctional giants that extend the capabilities of Telegram to some incredible boundaries, but, in my opinion, are the antonym of convenience.
So for example, to make a clickable text, before sending, I should write my message to the bot, select the desired markup (HTML or Markdown), confirm the action. If I found a mistake or something needs to be corrected in the post - it is too late. You need to re-select through the bot channel, write text, format, add a link, etc. Then again, confirm the action, then again, and then again. Uuf, but I just wanted to send a small message with a link to my subscribers!
A bot to add comments to posts? Have you seen? Yes, 50% of users, slowly scrolling the tape, just do not want to do such operations just to leave a comment. Another 20% are generally afraid of such manipulations. And now, we get our 30% output, excellent feedback, what can we say.
Total
Despite all the above, I believe that over time, the bots and the Telegram itself will evolve and improve, become more and more functional and convenient. There are all prerequisites for this, and each update only confirms this.
It might have seemed to you that in some moments I was too nagging, perhaps even so, but the whole experience of user interaction is being built, it would seem, on trifles and small details.
This was my quick review of the UX / UI telegram. A lot of things are left behind the scenes, and if you like it, then next time I will definitely tell about them. And that's all, do not repeat the mistakes described above, work, develop and delight those around you with beautiful, and most importantly, convenient interfaces!